
Pass rS B? fg 

Book— JLjSJuT 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 112. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



PRELIMINARY REPORT ON THE 
ALFALFA WEEVIL. 



BY 



F. M. WEBSTER, 

In Charge of Cereal and Forage Insect Investigations. 



Issued May 14, 1912. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



Monograph 



/ 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 112. 

L O. HOWARD, Entomologist and Chief if Bureau. 



PRELIMINARY REPORT ON THE 
ALFALFA WEEVIL. 4 (* 9 



BY 



F. M. WEBSTER, 

In Charge of Cereal and Forage Insect Investigations. 



Issue]) May 14, 1912. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912, 












h 






'-. 



BUREAU OF ENTOMOLOGY. 

L. O. Howard, Entomologist and Chief of Bureau. 

C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. 

R. S. Clifton, Executive Assistant. 

W. F. Tastet, Chief Clerk. 

F. II. Chittenden, in charge of truck crop and stored product insect investigations. 

A. D. Hopkins, in charge of forest insect investigations. 

W. D. Hunter, in charge of southern field crop insect investigations. 

F. M. Webster, in charge of cereal and forage insect investigations. 

A. L. Quaintance, in charge of deciduous fruit insect investigations. 

E. F. Phillips, in charge of bee culture. 

D. M. Rogers, in charge of preventing spread of moths, field work. 

Rolla P. Gurrie, in charge of editorial work. 

Mabel Colcord, in charge of library. 

Cereal and Forage Insect Investigations. 

F. M. Webster, in charge. 

Geo. I. Reeves, W. J. Phillips, C. N. Ainslie, E. 0. G. Kelly, T. D. Urbahns, 
Harry S. Smith, Geo. G. Ainslie, J. A. Hyslop, W. 11. Walton, J. T. Monell, 
J. J. Davis, T. II. Parks, R. A. Vickery, V. L. Wildermuth, E. G. Smyth, 
Herbert T. Osborn, Philip Luginbill, C. W. Creel, E. J. Vosler, R. N. Wil- 
son, Vernon King, entomological assistants. 

Nettie S. Klopfer, Ellen Dashiell, preparators. 

Miriam Welles Peeves, collaborator. 
2 

n nv 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 

Bureau of Entomology, 

Washington, D. C, January 2, 1912. 
Sir: I have the honor to transmit herewith, for publication as 
Bulletin No. 112 of this bureau, the manuscript of a preliminary 
report on the investigation of the alfalfa weevil in Utah and adjacent 
States. The investigations of the Bureau of Entomology in coopera- 
tion with the Utah Agricultural Experiment Station began April 1, 
1910, and still continue. The period covered by this report is from 
April 1, 1910, to November 15, 1911. From April 1, 1910, to April 
1, 1911, the bureau was represented in the investigations with but one 
assistant. Since that time the force has been increased until eight or 
nine persons have been from time to time employed. The information 
given is exactly what the title of the bulletin implies, preliminary in 
nature and not to be taken as conclusive in all cases. It is simply a 
short account of what has been done within the period of time just 
indicated. 

Respectfully, L. O. Howard, 

Entomologist and Chief of Bureau. 
Hon. James Wilson, 

Secretary of Agriculture. 



CONTENTS 



Page. 

Introduction 9 

First appearance of the alfalfa weevil in the United States 9 

Spread of the pest 10 

Investigations by the Utah Experiment Station 11 

( '< operation of the Bureau of Entomology and the Utah Experiment Station. . 12 

Cooperation with other bureaus of the United States Department of Agriculture. 14 

Variety experiment 14 

Investigations of vertebrate enemies 15 

The insect not correctly determined 15 

Appearance of a second species in Utah • 15 

Description and seasonal history of the alfalfa weevil 15 

Egg-laying peri< id 19 

Evidence of a partial second generation 20 

The larva 21 

Larval period 22 

Cocooning and pupating 23 

Im m id plants 24 

Migration and diffusion 25 

Field experiments in destroying the alfalfa weevil 26 

Street-sweeper experiments 27 

Wire-brush experiment 27 

Cultivation in connection with irrigation 29 

Burning machine 29 

Reduction in quality of hay caused by the alfalfa weevil 30 

Natural enemies 30 

Invertebrates 31 

Predaceous enemies 31 

A native true parasi te 34 

Introduced parasites 34 

Egg parasites 35 

Mymarid egg parasite 35 

Pteromalid egg parasite 35 

Parasites of larvae and pupa? 3G 

Pteromalid larval parasite 36 

Other parasites 38 

Vertebrates 40 

Fungous enemies 41 

Index 43 

5 



ILLUSTRATIONS 



PLATES. 

Page. 

Plate I. Conditions favoring the spread of the alfalfa weevil. Fig. 1 — 

Volunteer growth of alfalfa on vacant lots in Salt Lake City, Utah. 

Fig. 2.— Volunteer alfalfa growing along the right of way of the 

Oregon Short Line Railway, a short distance north of Salt Lake 

City, Utah 12 

II. Hibernation of the alfalfa weevil. Figs. 1, 2.— Hibernating places 
of the alfalfa we.evil along fences and borders of fields in the 
vicinity of Salt Lake City, Utah. Fig. 3.— One of the main irriga- 
tion ditches in the Salt Lake Valley, a favorable hibernating 
place for alfalfa weevils 16 

III. Injury wrought by the alfalfa weevil. Fig. 1.— One of the worst 

infested fields in the Salt Lake Valley, showing injury to the first 
crop of alfalfa, which was left uncut. Fig. 2.— (a) Bunch of 
alfalfa uninjured by the alfalfa weevil; (b) bunch of alfalfa badly 
injured by the alfalfa weevil, showing growth made by first crop 
in the badly infested fields 20 

IV. Injury wrought by the alfalfa weevil. Fig. 1.— Crop secured from 

first cutting of one of the worst infested fields. Fig. 2.— First 
cutting from another field damaged from attack by the alfalfa 
weevil. Fig. 3.— First cutting secured from one of the fields of 

alfalfa slightly injured by the attack of the weevil 20 

V. Field experiments against the alfalfa weevil. Fig. 1. — Street 
sweeper in operation on alfalfa field after first crop was removed. 
Fig. 2. — Second crop ready to cut in field on which street sweeper 
was used June 14. Fig. 3.— Second crop of alfalfa growing on 

field where no treatment was given 28 

VI. Field experiments against the alfalfa weevil. Fig. 1 .—Wire-brush 
cultivator in operation on alfalfa field after first crop was removed. 
Fig. 2.— Second crop of alfalfa growing nicely as a result of treat- 
ment given. Fig. 3. — Condition of untreated fields about June. . . 28 
VII. Field experiments against the alfalfa weevil. Fig. 1.— Second crop 
of alfalfa, estimated at 2 tons per acre, secured from field treated 
with wire-brush cultivator. Fig. 2. — Fourth crop of alfalfa 
secured from field where brush cultivator was used. Fig. 3.— 

Condition of field used as check (PI. V, fig. 3) 28 

VIII. Field experiments against the alfalfa weevil. Fig. 1.— Alfalfa field 
after first crop was removed, severely disked preparatory to appli- 
cation of "mudding" process against alfalfa weevil. Fig. 2. — Fol- 
lowing the irrigation water with a drag, to puddle the weevils in 

the mud 28 

IX. Field experiments against the alfalfa weevil. Fig. 1.— Second crop 
of alfalfa in field treated by the "mudding" process. Fig. 2 — 
Condition of untreated fields at time photograph shown in figure 1 
was taken. Fig. 3.— Patch of first crop left in field shown in 
figure 1, showing how larvae were disseminated from the first crop 
into the field where the weevil had been killed by the "mud- 
ding " process 28 

7 



8 ILLUSTRATIONS. 

Page. 
Plate X. Fig. 1. — Burning machine experimented with as a method of 
destroying the alfalfa weevil. Fig. 2. — Boxes containing para- 
sites of the larvae and pupae of the alfalfa weevil, showing how 
this material was imported from Italy. Fig. 3. — Boxes of para- 
site material imported from Italy which contain egg parasites 

of the alfalfa weevil 32 

XI. Introduction of parasites of the alfalfa weevil. Figs. 1, 4. — Type 
of cages in which larval and pupal parasites of the alfalfa weevil 
were reared in the laboratory. Figs. 2, 3. — Boxes sealed and 
fitted with glass tubes into which imported parasites emerged 

and were separated in the laboratory 36 

XII. Figs. 1, 2. — Field cages used in hibernation experiments on the 
alfalfa weevil. Fig. 3. — Planting a colony of imported para- 
sites of the alfalfa weevil in Utah in an alfalfa field 36 

XIII. Figs. 1, 2. — Laboratories of the Bureau of Entomology, United 
States Department of Agriculture, at Salt Lake City and Mur- 
ray, Utah 40 

TEXT FIGURES. 

Fig. 1. The alfalfa weevil (Phytonomus posticus) : Adult 10 

2. The clover-leaf weevil (Hypera punctata): Stages and work 16 

3. The alfalfa weevil: Eggs 17 

4. The alfalfa weevil: Larvse attacking foliage; eggs in stem 18 

5. The alfalfa weevil: Larva 21 

6. The alfalfa weevil: Cocoon 23 

7. The alfalfa weevil: Pupa 24 

8. The alfalfa weevil: Adults attacking sprig of alfalfa 24 

9. Nine-spotted lady-beetle (Coccinella 9-notata): Adult, larva 31 

10. Convergent lady-beetle (ITippodamia convergens): Adult, pupa, larva.. 31 

11. The two-spotted Collops (Collops bipunctatus): Adult 32 

12. A predaceous mite, Pediculoidcs ventricosus: Adult female before the 

abdomen has become inflated with eggs and young 32 

13. Pediculoides ventricosus: Adult female after the abdomen has become 

inflated with eggs and young 32 

14. A predaceous mite, Erythrseus arvensis: Adult 33 

15. Anaphcs sp., a mymarid egg parasite of the alfalfa weevil 34 

16. Imported pteromalid egg parasite of the alfalfa weevil: Adult 35 

17. Larva of pteromalid egg parasite of the alfalfa weevil 36 

18. Pupa of pteromalid egg parasite of the alfalfa weevil 36 

19. Pteromalid parasite of larva and pupa of the alfalfa weevil: Adult 

female 37 

20. Pteromalid parasite of larva and pupa of the alfalfa weevil: Adult male. 37 

21. Pteromalid parasite of larva and pupa of the alfalfa weevil, showing eggs 

in place and enlarged figure of same 38 

22. Pteromalid parasite of larva and pupa of the alfalfa weevil, showing 

parasite larva 38 

23. Larva of pteromalid parasite attacking pupa of alfalfa weevil 38 

24. Pupa of pteromalid parasite shown in figures 22 and 23 38 

25. Canidiella cureulionis, a parasite of the alfalfa weevil: Adult female 39 

26. Itoplectis masculator, a parasite of the alfalfa weevil: Adult female. ... 40 

27. ('ocnnn of the alfalfa weevil, showing cocoon of the parasite Canidiella 

ntrculionis within 41 



PRELIMINARY REPORT ON THE ALFALFA WEEVIL. 



INTRODUCTION. 

The alfalfa weevil belongs to a genus or group of beetles all of the 
members of which attack clover, alfalfa, and closely allied plants. 
Even before the appearance of this one, Phytonomus posticus 1 Gyll. 
(fig. 1), in our midst several other species had been introduced from 
Europe, had become established in our fields, and had spread to a 
greater or less extent over the country. 2 After becoming fully devel- 
oped in early summer, all apparently have the same habit of scattering 
themselves over the country, a little later crawling into any secluded 
place that they can find, there to pass the winter. Years ago a lady 
residing in Michigan and spending the summer in New York, where 
one species of these beetles, Hypera punctata (fig. 2), was at the 
time very abundant, on her return home and on unpacking her 
trunk found some of them ensconced among the contents. They had 
in all probability secreted themselves, either in the trunk itself while 
it was being packed, or else among articles of clothing exposed out of 
doors prior to being packed in the trunk. 

The alfalfa weevil is found in Europe, western Asia, and northern 
Africa, where, though it sometimes becomes abundant, it is not 
especially destructive. The foregoing will illustrate the numerous 
ways whereby it might have been introduced into this country in 
articles of commerce, in household goods, or among other belongings 
of immigrants coming from those countries. 

FIRST APPEARANCE OF THE ALFALFA WEEVIL IN THE UNITED 

STATES. 

The pest was first reported on the outskirts of Salt Lake City, 
Utah, in the spring of 1904. At that time it had seriously injured 
several acres of alfalfa, the first crop being damaged fully one-half 
and the second crop practically destroyed. The following spring, 
1905, its work was observed several miles way. The particular 
locality where the pest was first observed is on the eastern border of 
the city. Although not far distant from nurseries, it is not in close 

l In a recent paper, "The Genera Hypera and Phytonomus in North America north of Mexico" 
(Annals of the Entomological Society of America, vol. 4, no. 4, pp. 3S3, 473, pis. 24-34, December, 1911), 
Prof. E. G. Titus has given this species as P. posticus Gyll. Phytonomus punctalus had already 
been placed in the genus Hypera by European authors. 

2 Phytonomus punctatus Fab.: See Report of the Commissioner of Agriculture for 1881-82, pp. 171-179; 
Phytonomus nigrirostris Fab.: See Bui. 85, Part I, Bur. Ent., U. S. Dept. Agr., 1909. For other species of 
the genus see paper by R. L. Webster, Ent. News, vol. 20, pp. 80-82, 1909. 

9 



10 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

proximity to any railway; it is, on the other hand, among the habita- 
tions of the more humble class of people, such as have come from for- 
eign countries. The correct inference, therefore, would seem to be that 
it was introduced with nursery stock or in the household effects of 
immigrants. The pest had gained a foothold, doubtless, years earlier, 
but had increased from perhaps a single pair and was too few in num- 
bers to attract attention up to the time when it had become destruc- 
tive over several acres and when it had probably spread in limited 
numbers far beyond. In the immediate vicinity of this seriously 
infested field, and indeed throughout the country about Salt Lake, 
alfalfa long ago escaped from cultivation and now grows as a weed 
generally on vacant lots (PL I, fig. 1) and other uncultivated areas 
like roadsides and railroad rights of way (PI. I, fig. 2), so that it 
would now be impossible to determine, even approximately, the 
exact time and location of the original landing of 
the first individuals in Utah. As a matter of fact 
the insect might easily have been brought into 
the country again and again and have perished 
because the locality in which it ended its voyage 
was destitute of growing alfalfa. 

SPREAD OF THE PEST. 

From the single infested alfalfa field near Salt 
Lake, the only one known up to the year 1904, 
Fio.i.-The alfalfa weevil tne P est evidently became somewhat widely dif- 
(Phytonomus posticus)-, fused and by the following year was found sev- 
^^uLteSS oral miles distant to the southeast, It was not, 
however, until 1907 that it was brought to the 
attention of the Utah Experiment Station and not until 1908 that 
attention was called to the matter in print by Prof. K. G. Titus, 1 
entomologist of the Agricultural College and Experiment Station, 
although by the fall of 1907 it had spread over all of the alfalfa-grow- 
ing section lying immediately east of Salt Lake and Murray. 2 By 
July 1, 1910, the infested area covered the greater part of Salt Lake 
and contiguous portions of adjoining counties, aggregating an area 
approximately 60 by 70 miles in extent. 3 

Up to September, 1911, the insect had extended its area of diffusion 
directly northward as far as Tremonton, east to Evanston, Almy, 
and Lyman, Wyo., and northeast to Cokeville, Wyo., Randolph and 
Laketown, Utah, and Fish Haven, Idaho. 

' Deseret Farmer, Sail Lake City, Utah, September 2(\ and < >ctober :s, 1908. 

2 Bui. 110, Utah Agr. Coll. Exp. Sta. The Alfalfa Leaf-Weevil, by E. <i. Titus, Logan, Utah, September, 
1910. 
s Loc. cit., map 1. 




PRELIMINARY REPORT ON ALFALFA WEEVIL. 11 

INVESTIGATIONS BY THE UTAH EXPERIMENT STATION. 

From the time the attention of the Agricultural Experiment Station 
authorities at Logan, Utah, was called to the pest and its destructive 
proclivities they began to investigate and experiment with a view of 
overcoming its ravages. Following the breeding season of 1909, how- 
ever, the situation became so alarming as to make it clear that the State 
of Utah could not hope to cope with the pest single-handed. Besides, 
there was no longer a doubt that it would soon spread to alfalfa 
fields in other States, thus becoming a matter of interstate concern. 

On August 4, 1909, his excellency William Spry, governor of Utah, 
appealed to the honorable the Secretary of Agriculture for assistance 
in controlling the insect and, if possible, preventing its spread into 
other States. 

It was exceedingly unfortunate that this outbreak of the pest was 
not made known long before in order that it might have been investi- 
gated, for at this time it had become too widespread and destructive 
to be dealt with by any ordinary force of men. Besides, at this time 
the funds available with which to carry on investigations were 
wholly inadequate. 

The appropriations made for the Bureau of Entomology for the 
fiscal year 1910-11 gave a slight increase of funds, $2,000 of which 
provided for cooperation with the State of Utah in investigation of 
the alfalfa weevil. None of this sum would, however, become avail- 
able until July 1, 1910, after the season for the investigation of the 
insect had largely passed for the year. In view of the seriousness of 
the situation Mr. C. N. Ainslie was sent to Salt Lake, Utah, to take 
up cooperative work, April 1, 1910, lack of available funds prohib- 
iting any further detail for the purpose. 

At this time the entire cooperative force consisted of but two 
trained men, Mr. Ainslie, of the Bureau of Entomology, and Prof. 
E. G. Titus, of the Utah Agricultural College and Experiment 
Station, and Mr. Sadler, a student assistant, also from the experiment 
station. 

From the fact that the experiment station people had carried out 
a number of field experiments against the weevil and had other 
experiments in view, and because of the bureau's limited funds for 
this work, it was deemed best that Mr. Ainslie devote his principal 
time to a close study of the insect itself and its habits, leaving the 
field experiments to be carried on by and under direction of the 
experiment station. The results and information thus obtained up 
to July 1, 1910, were embodied in Bulletin No. 110 of the Utah. Ex- 
periment Station, by Mr. Titus, of which the author thereof has given 
the following synopsis: 

The alfalfa leaf-weevil is a small, oval, brown snout-beetle, about ^ of an inch long, 
that is attacking alfalfa in Utah. It is not a native species but has come to Utah from 
Europe. 



12 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

It feeds on plants belonging to the alfalfa family, injuring all parts of the plant above 
ground . 

The eggs are laid in the spring and early summer in the stems or on the buds and 
leaves, and hatch in about ten days. The young or larvae are small alfalfa-green 
worms with a black head ; they never become much more than one-quarter of an inch 
in length when full grown. They feed on and in the leaf-buds, in the stalks and on 
the leaves. 

The larvae have no true legs and have the habit of feeding or resting in a curled 
position. 

When full grown, about 50 or 60 days after hatching, they go to the ground and spin 
around them a lace-cocoon, in which, in about fourteen days, they have turned into 
the full-grown, hard-shelled adult. 

This adult feeds on the stems, leaves and buds for several weeks and in August goes 
into hibernation for the winter, seeking any well sheltered place. 

The insect now occurs in Salt Lake, Davis, Weber, Morgan, Summit, Wasatch, 
Utah, and Tooele Counties, and threatens to eventually reach all our alfalfa growing 
regions. It spreads rapidly in the adult or beetle stage by flying in spring and summer 
and by being carried with articles shipped from an infested region, and on railroads, 
in wagons and automobiles, traveling through the places where it occurs. 

It is recommended that alfalfa be disced in early spring to stimulate it to better 
growth. That the first growth be cut when the most of the eggs have been laid (middle 
of May), and then brush-drag the field thoroughly. 

Sheep may be pastured on the fields at this time for two weeks, and alfalfa then 
watered and a good crop will usually be assured. 

Gathering machines to capture the larvae and beetles have given good results when 
used on the fields at the time the insects are most numerous. 

Fields should be brush-dragged again after the first crop has been cut. 

All weeds and rubbish should be cleaned from fields, yards, ditches and fence 
rows so that there will be less opportunity for the weevils to find winter shelter. 

Alfalfa should not be allowed to grow more than seven or eight years in infested 
districts. 

The amount of work that the Utah Experiment Station did with 
its limited means and lack of trained men is certainly most com- 
mendable, and it is difficult to see wherein the course adopted by the 
station director (Dr. E. D. Ball) and his subordinates could have been 
improved upon. It was from the beginning an unequal contest, and 
the only wonder is that so much good was accomplished with the 
limited means available. 

COOPERATION OF THE BUREAU OF ENTOMOLOGY AND THE 
UTAH EXPERIMENT STATION. 

There was the same basis of cooperation between the Bureau of 
Entomology and the Utah Experiment Station from April 1 until 
September 1, 1910, when Prof. Titus left the State, leaving Mr. 
Ainslie, and for a few weeks Mr. Sadler, to carry on the work. 
In the agricultural bill covering the fiscal year from 1911-12, 
under appropriations for cereal and forage insect investigations, 
$10,000 of this appropriation was made immediately available on 
passage of the act, to enable the bureau to take up investigations of 
the alfalfa weevil promptly in the spring of 1911. With the aid of 



Bui. 1 1 2, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate I. 








FXG.I.-Volunteer growth of alfalfa on vacant lots In Salt Lake City, Utah The alfalfa 
plant beside the hat contained at the time approximately 1,200 to 1,300 eggs, l&u, 
was in the midst of the egg-laying time. (Original.) 




FlG . 2.-Volunteer alfalfa growing along^e right of way of the Oregon Short Line Railway a 
short distance north of Salt Lake City, Utah. (Original.) 

Conditions Favoring the Spread of the Alfalfa Weevil. 



COOPERATION OF BUREAU AND STATION. 13 

this fund, on April 1 a corps of entomologists was sent to Salt Lake 
City, Utah, for the purpose of carrying out a thorough study of the 
insect and its ravages, with special reference to methods of control. 
Gradually other assistants were detailed, until the number employed 
in and about Salt Lake was increased to nine, exclusive of the student 
assistant detailed from the State Agricultural Experiment Station. 

The primary object of this work was, so far as possible, to restrict 
the insect to the area it then occupied and to use every effort, by 
field experiments in measures of control, to devise means of lessening 
its destructiveness. 

In the meantime it has been learned definitely that the alfalfa 
weevil was largely held in check in its native home by its natural 
enemies. Mr. W. F. Fiske, in charge of the Gipsy Moth Parasite 
Laboratory, having been detailed for work in Italy, kindly volunteered 
to look into .the matter of natural enemies of the weevil and, so far 
as was possible without interfering with his other duties, to send over 
to this country any insect enemies that seemed to him susceptible 
of colonization in Utah. The object of this was to get these insect 
enemies established, in so far as it was practicable to establish them, 
at the earliest possible date, in order that they might have the oppor- 
tunity to diffuse themselves during the spring of 1911. The value 
of Mr. Fiske's services at this time and in this direction can hardly 
be overestimated. A more detailed account of this matter will be 
found under a discussion of the introduction of the natural enemies 
of the alfalfa weevil. 

Very naturally the alfalfa weevil work divided itself into two 
branches: (1) The field work, which included all mechanical measures 
for controlling the pest in the field; and (2) the work, necessarily 
carried out largely in the laboratories at first, involved in the care 
and management of the parasitic material dispatched by Mr. Fiske 
from Italy. After the beginning of the fiscal year 1911-12 the experi- 
ment station was able to add but slightly to the force of investigators. 
By this time, however, the annual generation of the weevil had devel- 
oped to the adult stage and laboratory investigations had largely 
decreased. 

While, as shown, the experiment station, owing to circumstances 
not under its control, was not able to put into the field men trained 
for this kind of work, the bureau was able by the aid of the imme- 
diately available fund to overcome this difficulty. In the meantime, 
however, the experiment station did its full share in other directions. 
Dr. Ball, director of the station, did not hesitate to use his personal 
and official influence whenever and wherever it could be of service in 
advancing this work. Besides this, in a great many cases he was 
able to relieve the bureau of expenses of field investigations as well 
as to carry a number of other items of expense for which it would 



14 PKELIMINARY EEPOET ON ALFALFA WEEVIL. 

have been impracticable for the bureau to have provided. It may 
be stated, then, that from April 1 to September 1, 1910, the coopera- 
tive work was largely under the direction of Prof. E. G. Titus of 
the experiment station. From September, 1910, to April, 1911, it 
was mostly carried on personally by Mr. C. N. Ainslie. During the 
spring and summer of 1911 the investigation was carried on under 
the general direction of those connected with the Bureau of Ento- 
mology. Outside of the work on parasites, which has been carried 
on wholly by the bureau, it is not possible distinctly to indicate just 
what part of the cooperation was carried on by either the bureau or 
the experiment station. This combination has been for the purpose 
of accomplishing the greatest amount of good, and there has been no 
inflexible line separating the work of the two cooperative bodies. As 
a matter of fact, the results obtained could not have been secured 
under any other arrangement or with less unselfish feeling than has 
existed among those engaged in the investigation. 

COOPERATION WITH OTHER BUREAUS OF THE UNITED STATES 
DEPARTMENT OF AGRICULTURE. 

Observations made by Mr. W. F. Fiske in the vicinity of Naples, 
Italy, during the spring of 1910 appeared to indicate a possible 
preference on the part of the alfalfa weevil for certain varieties of 
alfalfa. Those varieties, notably, having a slender stem appeared 
to be less freely attacked as compared with those varieties having 
more robust stems. It was with the view of perhaps being able to 
find a variety of alfalfa more or less objectionable to the alfalfa weevil 
that a cooperative experiment was taken up with the Bureau of 
Plant Industry. 

Variety Experiment. 

The Chief of the Bureau of Plant Industry, therefore, detailed Mr. 
Roland McKee, of the Office of Forage Crop Investigations, to super- 
intend the seeding of a number of varieties of alfalfa (Medicago 
sativa) and the following closely related species : Medicago falcataLi., 
M. ruthenica (L.) Trautv., M. lupulina L., M. ciliaris (L.) All., M. 
echinus Lam., M. hispida nigra (Willd.) Burnet, M. liispida confinis 
(Koch) Burnet, M. hispida terebellum (Willd.) Urban, M. muricata 
(L.) All., M. orbicularis (L.) All., and M. scutellata (L.) Mill. The 
tests of these varieties are being conducted on a farm in the vicinity 
of Salt Lake City, Utah. 

Such observations as it has been possible to make upon the young 
plants involved in this experiment will be found recorded under food 
plants. It will of course be understood that the most valuable and 
decisive information bearing upon the relative extent of attack in 
these different varieties of alfalfa can not be observed until the spring 
of 1912. Therefore the information now given must be regarded as 
only initiative. 



description and seasonal history. 15 

Investigations of Vertebrate Enemies. 

In order to determine what assistance might be expected from birds 
and other animals besides insects, arrangements were made with the 
Biological Survey to send an assistant to Salt Lake in order to carry- 
out extended investigations along this line. Mr. E. R. Kalmbach 
was detailed for this work by the Chief of the Biological Survey and 
proceeded to Salt Lake, Utah, making continuous observations there 
from May 7 to July 5, 1911. 

It is not possible at the present time to give the results of this work 
in detail, but a list of the vertebrate enemies observed attacking the 
alfalfa weevil will be found under the heading Natural Enemies. 

THE INSECT NOT CORRECTLY DETERMINED. 

In the bulletin of the Utah Experiment Station, to which reference 
has already been made, the name of the insect is given as Phytonomus 
murinus Fab., and this name was also applied to the same insect by 
the writer in Circular No. 137 of the Bureau of Entomology, issued 
April 20, 1911. It had been so determined by one of the best 
American authorities on this order of insects. It has, however, 
proved to be a closely related insect (Phytonomus posticus Gyll.), 
much more common and injurious to alfalfa in Europe, western 
Asia, and northern Africa, and in these countries known generally as 
P. variabilis Hbst., meaning literally the variable Phytonomus. It 
is, however, less destructive in the Eastern Hemisphere than it bids 
fair to be in this country, because of its natural enemies at home, 
which, as it appears, were not brought over with it when it was first 
introduced. 

APPEARANCE OF A SECOND SPECIES IN UTAH. 

A much larger species, Hypera punctata Fab. (fig. 2), the clover- 
leaf weevil, has recently been found about Malad, Idaho, by Mr. 
II. T. Osborn, and about Ogden, Utah, by Mr. E. J. Vosler, both 
of this bureau. This is a larger insect than the alfalfa weevil, but 
may be confused with it by the ordinary farmer. It had not before 
been observed between the Rocky Mountains and the Cascades. 

While known as a clover insect, this last beetle did some damage 
to alfalfa in Virginia during June, 1910. 

DESCRIPTION AND SEASONAL HISTORY OF THE ALFALFA WEEVIL. 

The fully-developed alfalfa weevil, Phytonomus posticus Gyll. (fig. 1), 
is a small, rather insignificant appearing beetle, slightly under one- 
fourth of an inch long, of a brown color, mixed with gray and black 
hairs arranged in indistinct spots and stripes on the back, as shown 
in figure 1 . Rubbed individuals may be very dark, verging on black. 



16 



PRELIMINARY REPORT ON ALFALFA WEEVIL. 



The beetles pass the winter hidden away among matted grass or 
other similar vegetation, including alfalfa, and, indeed, among most 
kinds of rubbish anywhere, wherever they will be protected from the 
weather. The beetles have also been found in early spring under 
clods and about the crowns of alfalfa plants where the ground had 
been roughly cultivated the previous autumn. The overgrown mar- 
gins of fields and irrigation canals and ditches afford excellent places 
for hibernation, some of which are shown in Plate II, figures 1, 2, 
and 3. 

With the first warm weather in spring the beetles become active 
and diffuse themselves over the alfalfa fields, feeding upon any living 

part of the plants that 
have escaped the win- 
ter or, as soon as it 
commences to push 
forth, on the fresh 
growth, both leaf and 
stem. During some 
years the beetles are 
abroad in the fields in 
Utah early in March; 
in other and colder 
springs it may be April 
before they bestir 
themselves. Latitude 
and elevation, with 
the consequent modi- 
fications of tempera- 
ture, will have much 
to do in deciding the 
time of emergence 
from winter quarters 

Fig. 2.— The clover-leaf weevil (Hypcra punctata): a, Egg; b,b,b,b, insprintj. Thevalsoto 
larvsc feeding; /.cocoon; /.beetle; A - , same, dorsal view. (6,/, i. Natural ± , 1 -i A 

size; k, enlarged; «, greatly enlarged.) (From Riley.) SOme extCllt ^bemate 

in the alfalfa fields. 
As soon as the beetles have spread from their winter quarters out 
over the fields they pair, and the females are ready to deposit their 
eggs (figs. 3, 4). As a matter of fact, however, pairing has been 
observed in the fall, and females taken while hibernating are ob- 
served to lay 75 per cent of fertile eggs. According to the notes of 
Mr. Fiske, made in Italy, they may place their eggs in the old, dead, 
overwintered stems or even in the dead stems of plants other than 
those of alfalfa, but in Utah the beetles refused to oviposit in dead 
stems in the laboratory cages. According to Dr. Giovanni Martelli, 1 
at Portici in 1909 the first adults which he obtained appeared toward 




1 First eontribution to the biology of Phytonomtu variabilis Berbrt. Rollettino del Laboratoria di Zoo- 
logia Generale e Agraria della R. Seuola Superiore d'Agrieoltura in l'ortiei, vol. 5, March, 1911. 



1 1 2, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate II. 





Figs. 1 and 2. — Hibernating places of the alfalfa weevil along fences and borders of fields 
in the vicinity of Salt Lake City, Utah. (Original.) 




Fig. 3.— One of the main irrigation ditches in the Salt Lake Valley, a favorable hiber- 
nating place for alfalfa weevils. Photographed July 7, 1911. (Original.) 



Hibernation of the Alfalfa Weevil. 



DESCRIPTION AND SEASONAL HISTORY. 17 

the end of April; at Acicastello in 1910 they appeared during the 
first part of the second half of April. The maximum birth at Portici 
in 1909 took place toward the end of the second decade of May and 
the last adults were hatched near the end of May. At Acicastello 
the maximum birth took place in the first decade of May and the 
last were hatched during the second decade of the same month. 

The females do not, however, always confine themselves to alfalfa 
stems in ovipositing. On April 18, 1911, Mr. T. H. Parks found eggs 
of Phytonomus in punctures similar to those made in alfalfa in the 
stems of the ground plum, Astragalus arietinus. Later Mr. C. N. 
Ainslie found a number of these eggs in similar punctures, also in the 
stems of this plant, there being usually six or eight eggs in each 
puncture. Afterwards Mr. Ainslie found larva? feeding on Astragalus 
utahensis. 

A few days before, Mr. Parks had also found eggs deposited on the 
surface of leaves, on bits of trash, on the inside of a split stem of 
grass, and, in one case, upon the bare ground. 

In a very early spring some of the eggs may Jf|E^~ 
be deposited outside of the plant, but evidently , |fip \, jjj| 
tins is not usual and occurs mostly when the jfef & >_- 

growing stems of alfalfa are too small or not suffi- : : s : ^**£ 
ciently numerous to satisfy the requirements of Fm . 3 .-The aiaura weevil: 
the females in this direction. In preparing for Eggs. Greatly enlarged, 
egg deposition the female punctures the stem (Author's illustration.) 
with her beak. The punctured stems and a group of these eggs in 
place are shown in figure 4. 

The method of oviposition has been described by Mr. Titus. 1 

Observations were made by Mr. C. N. Ainslie in which he found 
that oviposition seemed to be accomplished by forcing the beak into 
the fleshy tissues of the stem, sometimes into a hollow stem, in which 
case the eggs are merely placed in the natural cavity. Where placed 
in a leaf petiole, as is sometimes the case, the cavity for the eggs 
must be necessarily eaten out. Generally in these eaten cavities only 
4 or 5 eggs are placed, while in the hollow stems 15 or 20 seem 
not uncommon. Once or twice Mr. Ainslie found eggs placed below 
the enlarged base of the petiole. In this case the eggs were placed 
in position through a hole made through the base of the petiole 
and the mass of eggs was well protected by the hairy leaf buds 
and unfolded leaflets behind the base of the petiole. Once in a 
while the hole into the stem is eaten and the beak not merely forced 
in, in which case the gleam of the yellow eggs can be seen through 
the tunnel into the stem. When the opening is forced it is left more 
or less rilled with fibers that have been disrupted or forced aside by 
the beak and the ovipositor. These fibers are often blackened from 

i Bulletin 110, Utah Agr. Coll. Exp. Sta., pp. 3S-39, September, 1910. 
26200°— Bull. 112—12 2 



18 



PRELIMINARY REPORT ON ALFALFA WEEVIL. 



some cause, perhaps simple oxidation, and appear quite different 
from the "feeding holes" that are much more common. ^ These latter 
are either saucer or cup shaped cavities eaten into the plant stem or 
punctures through the epidermis that are enlarged inside the stem. 

In one alfalfa stem Mr. Ainslie found 4 egg "nests," the holes being 
in pairs. These pairs were one-half to three-fourths of an inch 
between the separate holes, and each pair was in a separate node, the 

pairs perhaps 3 inches dis- 
tant from each other. There 
must have been 30 or 40 eggs 
at least in this one stalk. It 
was picked from a vigorous 
crown growing beside a ma- 
nure pile, and nearly every 
other stem in this crown con- 
tained eggs. These shoots 
were tall and had evidently 
grown rapidly. Indeed this 
seems to be the kind of stem 
chosen by this insect in 
which to place the eggs; 
shorter, woodier stems seem 
seldom to be selected for this 
purpose 

As observed by Messrs. 
Wilson and Paries, assistants 
of the bureau, the female 
beetle, after excavating the 
cavity for the eggs, inserted 
her ovipositor and laid a 
number of eggs before re- 
moving the ovipositor from 
the cavity. After this she 
began beating it up and down 
rapidly over the puncture as 
though pounding the orifice, 
sometimes but not always 
excreting a drop of watery 
material over thepuncture. This secretion when hardened appeared to 
seal the opening. In some cases the arrangement of the eggs in rows 
on each side of the puncture, as described by Mr. Ainslie, was verified. 
Mr. Titus has described the egg * as being oval, rounded at the ends, 
and when first deposited lemon-yellow in color. As the eggs incu- 
bate they become darker at one end and a deeper y ellow in the other 

i Bulletin 110, Utah Agr. Coll. Exp. Sta., p. 34, September, 1910. 




Fig. 4.— The alfalfa weevil: Larvi ■ attacking 
alfalfa, ami eggs, in situ; larva, enlarged, 
(Author's illustration.) 



DESCRIPTION AND SEASONAL, HISTORY. 19 

portions. Under the microscope the surface of the egg is very 
slightly roughened and sculptured. 

Mr. Ainslie, who made a careful study of the egg (fig. 3) at oviposi- 
tion and later, found that at time of laying the egg was a mere sac, 
the shell being little more than a transparent, homogeneous envelope 
or membrane. As segmentation proceeded this membrane became 
very faintly pitted, and under the microscope with proper illumina- 
tion barely discernible reticulations, both pentagonal and hexagonal, 
were apparent. Both ends and sides seemed equally reticulated, the 
areolation being perhaps a little smaller at the ends. After the larva 
emerges the shell that remains is a transparent structureless mem- 
brane with no trace of reticulation. 

The number of eggs placed in a cavity varies greatly, there some- 
times being not more than 2 or 3, ranging up to over 30; probably 10 
would be about the average number, although these figures are of 
course only approximate. Mr. Parks found that during the first half 
of April the number ranged from 3 to 18, averaging 7 or 8; during 
the last half and early May the number increased, 25 or 30 being the 
maximum, with an average of 8 or 9. With reference to the number 
of eggs that may be deposited in a single alfalfa plant, the one shown 
beside the hat in Plate I, figure 1, examined on April 23 — at which 
date oviposition was still in progress and the beetles preparing for 
oviposition were still exceedingly numerous in the fields — indicated 
that this plant at this date contained nearly if not quite 1,300 eggs. 
Of course, in fields where the alfalfa grew up thickly there would be 
a relatively less number per plant, but these figures serve to illustrate 
the origin of the countless myriads of larvse that swarm over the 
plants in an alfalfa field and render more easy of comprehension the 
destruction shown in Plate III, figure 1. The difference between 
uninjured and affected plants is shown in Plate III, figure 2, a and b. 
Other ravaged fields are shown in Plate IV, figures 1 and 2, in con- 
trast with figure 3 of same plate. 

In the Salt Lake Valley oviposition has been found to take place 
earlier on the bench lands than lower down in the valley itself. 

Egg-Laying Period. 

The period of egg laying is a matter of considerable significance, 
since in some degree it will decide the question of efficiency or prac- 
tical measures of control. As is usual with insects, after a female 
has exhausted her supply of eggs she dies and there is no second 
depositing of eggs by her during that season. The actual time 
required for the individual female to deposit her supply of eggs is of 
course influenced by the weather. In 1909 egg laying began in the 
fields early in April, and eggs were found in greatest abundance during 
the last of May and the first of June. In 1910 egg laying began early 



20 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

in March and was at its height by the middle of May, and Mr. C. N. 
Ainslie found eggs in a rearing cage where beetles were confined 
indoors as late as October 22, and others found them as late as Novem- 
ber 10, and Mr. E. J. Vosler on December 6, while larvae of all sizes 
were found rarely in the fields November 1. On this latter date the 
sexes were pairing in the fields and some of the females contained 
apparently mature eggs, but none could be found deposited in the 
fields. In 1911 Mr. Urbahns found eggs and very young larva' 
March 31, and adults active in the field on a warm day (January 
31, 1912); one feeding and one pair mating. 

The time required for the eggs to hatch after being deposited is, 
according to Mr. Titus, from 7 to 16 days, as observed by Mr. Ainslie 
about 10 days, and according to Mr. Parks's observations about 13 
days. The three series of observations were made during different 
years, 1909, 1910, and 1911, and, of course, under different tempera- 
ture conditions. It would seem as though more or less pairing 
is done in very late fall and the eggs deposited the following spring. 
Of course, the scattering eggs and larvae found throughout the late 
summer and fall have little economic importance except to indicate 
what might be expected in more southern localities, although even 
in Utah some eggs probably survive the winter. 

Evidence of a Partial Second Generation. 

The occurrence of larvae up to the approach of cold weather in late 
fall has already been noted. Some of these at least might be ac- 
counted for from the fact that overwintering females still containing 
eggs are found throughout July and early August ; but that others of 
these larvae are the offspring of parents developing during the pre- 
ceding spring is strongly indicated by the fact that the females 
depositing eggs from which larvae afterwards hatch are in perfect 
condition, urirubbed, and apparently fresh. 

Under date of October 19, 1910, Mr. Ainslie found that eggs were 
being deposited in his rearing cages, dropped at random on stems 
and leaves and even on the sides of the cage, but in no case did he 
observe them placed within the stem. There were in this cage 150 
adults, some of which were undeniably trim and fresh as though they 
had just emerged, while others were pretty well worn, and there were 
all intervening gradations. Adult females swept from alfalfa No- 
vember 2 were found to have oviposited two days later. Adults 
taken from the fields November 7 and kept indoors were found to 
have deposited eggs within 2 or 3 days prior to November 30. 

During the season of 1911 it was possible still further to substan- 
tiate the foregoing by an extensive series of observations carried on 
by several of those engaged in the investigation, and besides to add 
even more evidence that some of these late-appearing larvae are the 



Bui. 1 12, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate III. 




Fig. 1. — One of the worst infested fields in the Salt Lake Valley, showing injury to the first crop 
of alfalfa, which was left uncut. Photographed June 26, 1911. (Original.) 




Fig. 2.— a, Bunch of alfalfa uninjured by the alfalfa weevil. 
b, Bunch of alfalfa badly injured by the alfalfa weevil, 
showing growth made by first crop in the badly infested 
fields. Photographed June 20, 1911. (Original.) 



Injury Wrought by the Alfalfa Weevil. 



Bui. 1 1 2, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate IV. 




if 



§&d^3Pwt 



Fig. 1. — Crop secured from first cutting of one of the worst infested fields. Photographed 
June 9, 1911. (Original.) 




Fig. 2. — First cutting from another field damaged from attack by the alfalfa weevil. Photographed! 

June, 1911. (Original. ) 



>U>M**ml&,+«*b*«> 



VLMbk 




Fig. 3. — First cutting secured from one of the fields of alfalfa slightly injured by the attack of 
the weevil. Photographed June 2, 1911. (Original.) 



Injury Wrought by the Alfalfa Weevil. 



DESCRIPTION AND SEASONAL HISTORY. 21 

offspring of parents developing during the preceding spring. Eight 
apparently fresh adults taken from the field on August 18 by Mr. 
Urbahns were observed on the 21st to have oviposited to the number 
of about 20 eggs, in confinement. Nine additional eggs were found 
on the 23d. August 29, 10 adults, also seemingly fresh and un- 
rubbed, were confined in a glass vial, and the following day about 
50 eggs were found in the vial. Under the same date 112 beetles, 
supposed from appearances to belong to the spring generation, were 
collected by another member of the force at an elevation of about 
7,000 feet, and the following day 75 eggs were found in the box in 
which they were confined. Under the artificial conditions not all of 
these eggs hatched. This state of affairs continued and was observed 
by several of the men to occur up to the end of the season. 
While the beetles go into hibernation in nearly per- 
fect unrubbed condition, they emerge in spring with 
scales and pubescence removed to such an extent that 
they are almost black in color, smooth, and shining. 
This appearance so contrasts with that of the newly- 
emerged adults of the new generation that the latter 
can be easily separated at sight, and it was these latter 
that were again and again observed to oviposit and their 
eggs to hatch out larvae. 




The Larva. 



Fig. 5— The al- 
falfa weevil: 
Larva. Much 
enlarged. 

The larval stage is shown in dorsal view in figure 4 and (Author's u- 

. „ ° lustration.) 

in lateral view in figure 5. It is during this stage that 

the pest accomplishes the greatest destruction, although the beetles 

are of themselves capable of ruining the second hay crop of alfalfa. 

Mr. Titus ' states that soon after hatching from the eggs the larva 1 , 
which at that time are quite active, begin feediug in the interior of 
the stalk, sometimes remaining there for 3 or 4 days, and isolated 
examples have been found that have passed into the second stage, 
still inside the stalk. Larvae have been found inside hollow stems 
several inches away from the place where they hatched, working their 
way upward, and later issuing through a feeding puncture. Usually 
after 3 or 4 days they come out and work their way up the outside of 
the stems and conceal themselves in a leaf bud, usually at the tip of 
the plant. 

That the very young larvae are capable of traveling considerable 
distances to reach their food supply is not only indicated in Mr. Titus's 
published statement, but emphasized by the observations of Mr. C. N. 
Ainslie under date of April 28, 1910. The actions of newly hatched 

i Bulletin 110, Utah Apr. Coll. Exp. Sta., pp. 39, 40, September, 1910. 



22 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

larvae, as observed by him, were remarkably vigorous, very young 
ones exhibiting great energy as travelers. Their mode of progression 
is to reach forward and then, with a slight hump, to bring up the rear 
part of the body. The head is at once thrust forward again. About 
one move is made per second, and three propulsions will carry the body 
forward 1 mm. When in doubt as to the direction to be taken, the 
larva elevates the head and swings it from side to side until some 
decision is reached, when the journey is resumed. The larvae are 
positively phototropic. 

After working their way upward on the alfalfa stems the larvae 
begin to feed close down between the opening buds on the unfolding 
leaves. Their manner of feeding there, as observed by Mr. Ainslie, 
was by scraping off the epidermis with a sort of burrowing motion, 
leaving only the veins and fragments of uneaten tissue. This selec- 
tion of the terminal buds may be in part due to the shelter offered 
as well as to the more tender and succulent nature of the plant 
growth. Large numbers of young larvae may, however, be found 
feeding among the unfolding buds without being easily seen. This 
feeding is further described by Mr. Titus * as follows: 

In feeding, the larvae bore holes into the buds [see fig. 4], working their way in 
until they are often completely concealed inside the opening bud. The plant then 
sends out other buds below this point, and usually other young larvae are present to 
destroy these, so that at times the growing tips of the plants become so injured a-: to 
give these tips the appearance of a gall. As many as 15 young larvae have been found 
feeding in the terminal bud of one stalk. Sometimes, before they are fully developed, 
in the second stage, they pass out onto the leaves, at first eating the upper epidermis 
only. 

The larvae, after the usual habit of those of the genus to which it 
belongs, either cling around the edge of the leaf or feed in a curved 
position. This continual eating off of the fresh growth keeps the 
alfalfa so reduced that it does not produce a first crop. Seriously 
affected fields are shown in Plate III, figure 1, and Plate IV, figures 
1 and 2, while a field that has not suffered from such attack is shown 
in Plate IV, figure 3. From these illustrations a good idea of the 
damage done by the larvae to the first crop of alfalfa may be obtained. 

LARVAL PERIOD. 

From about 5 to S days after hatching from the egg the skin of 
the larva splits and the old skin is pushed off, leaving the larva in a 
new dress. This process is repeated after a period of from 12 to 20 
days and again after about 12 to 30 days, as observed by Mr. Titus. 
Mr. Ainslie in some instances got pupae in 18 to 20 days during May, 
1910. These variations in time are probably largely due to tem- 
perature, which again may be due in part to elevation. 

1 Bulletin 110, Utah Agr. Coll. Exp. Sta., pp. 40-42, September, 1910. 



DESCRIPTION AND SEASONAL HISTORY. 23 

When the larva is fully grown, it ceases to feed and seeks out some 
place in the crown of the plant among the litter and trash or on the 
ground among similar material, where it spins a cocoon (fig. 6). 

COCOONING AND PUPATING. 

The cocoon is composed of fine white threads and the construction 
by the apparently blind larva was in part observed by Mr. Ainslie, 
who describes its movements as follows: A larva was seen moving 
about in its snow-white, almost transparent, gauzy, unfinished cocoon. 
It proved to be spinning a closer mesh from within. Instead of 
spinning the silk from a gland that opened into its mouth, as was 
supposed, the fluid from which the silk is made is taken into the mouth 
apparently from a gland in the caudal segment. The larva applied 
its mouth to an opening or gland close to the anus, appeared to move 
its jaws slightly, and then, with a quick 
movement of the body, was straightened 
out as much as possible in its confined space, 
and instantly the head was applied to the 
inner network of the cocoon. A slender 
glistening thread was seen leaving the 
mouth, being attached glutinously to each 
thread that it crossed. The larva worked 
rapidly and nervously, nearly always car- 
rying its new thread in a rather straight 
line. From 30 to 50 seconds were required 
to discharge a single mouthful supplying 
thread for one-third or one-half a revolution fig. 6.— The alfalfa weevil:' cocoon. 
inside the cocoon. Mu?h en ^e^- (Author's uiu* 

ii i i ii tration.) 

When all the supply was exhausted, the 
head groped aimlessly about for a few seconds, then was applied to the 
caudal gland as before. The body would then straighten with a quick 
movement and almost instantly the thread would be again flowing as 
before. The new thread was guided skillfully across the meshes, rarely 
if ever following the line of a thread already laid. A very slight jar 
would cause a sudden halt for perhaps half a minute, then the opera- 
tion would hesitatingly proceed. As the irregularly oval cocoon is 
too small in any diameter to allow the larva to straighten out, the 
larva moved about by thrusting its small head into a mesh, swinging 
the body into the desired position; the head would then be moved 
to another mesh and the operation repeated. The fluidity and amount 
of the silk must vary as spinning progresses, the silk becoming more 
viscous or less copious as the cocoon approaches completion. 

The pupal period, according to Mr. Parks's notes, during the middle 
of May lasts about 9 days, the larva? spinning their cocoons about 5 
days before pupating. (A pupa is shown in fig. 7.) At the end 




24 



PRELIMINARY REPORT ON ALFALFA WEEVIL. 



of the season, however, during August, when the temperature is 
higher, the pupal period averages only 3 days, the cocoon being spun 
only about 36 hours before the larva pupated. The adult leaves the 
cocoon about a day after transformation, and unlike others of this 
genus does not devour the cocoon. Although the insect has passed 
through its transformation from egg to adult the injury 
it causes is by no means ended. The beetles them- 
selves not only feed upon the young growth (fig. 8), 
but gnaw off the bark of the stems, and, together 
with the larvse still in the fields, in this way prevent 
the alfalfa from springing up for weeks after the first 
crop of hay has been removed. Two of such fields 
are shown in Plate V, figure 3, and Plate VI, figure 3, 
the ground being almost as bare of growing plants as 
in figure 1, Plate VIII, where the ground has been 
torn up with a spring-tooth harrow. The beetles some- 
times cluster in great numbers upon a single plant, as 
illustrated in figure 8. 




Fig. 7.— The alfalfa 
w eevil: Pupa. 
Much enlarg d. 
(Author's illus- 
tration.) 



FOOD PLANTS. 

In a series of experiments carried out by Mr. P. H. Hertzog, larvse 
of Phijtonomus posticus were placed in cages on various food plants, 
both alone and with alfalfa, and it was found that they fed freely 
upon the following plants, in combination with alfalfa: 

Sweet pea, Lathyrus odoratus; Utah milk vetch, 
Astragalus utahensis; string bean, Phaseolus vulgaris; 
obtuse-leaved vetch, Vicia sp. ; narrow-leaved vetch, 
Vicia sp.; white clover, Trifolium rcpens; red clover, 
T. pratense; alsike clover, T. hybridum; yellow sweet 
clover, Melilolusindica(?);whitesweetclover, M.alba; 
Medicago lupulina; M. echinus; M. hispida nigra; M. 
hispida confinis; M. hispida terebellum; M. muricata; 
M. orbicularis; M. scutellata; black locus!,, Robinia 
pseudacacia; fenugreek, Trigonella foenumgrxcum. 

The following is a list of plants eaten by 
the larvse when no other food was offered, but 
refused when offered together with alfalfa: 

Hedysarum mackcnzii; Astragalus oreophilus; downy 

lupine, Lupinus; sp. chick pea, Lathyrus sativus; Vicia Flc - 8.— The alfalfa weevil: Adults 

atropurpurca; Vicia dispema; spring vetch, Vicia saliva ^f,*™ , on aml a,,!W ' kin s sprig of 
„ , . . ,__...,, . , , alfalfa. About natural size. (Au- 

alba; hairy or winter vetch, I icia villosa; spider plant, thor's illustration ) 
Clcomc serrulata. 

The following plants wore refused by the larvae even when no other 
food was offered : 

Everlasting pea, Lathyrus latifolius; round-leaved mallow, Malva rotundi/olia; birds- 
knot grass, Polygonum aviculare; garden pea, Pisum sativum; lamb's-quarters, Cheno- 
podium album; purslane, Portulaca oleracca; prickly lettuce, Lactuca scariola, perhaps 
var. ir.tcgrata; ground cherry, Physalis longi/olia(?) ; bitterweed, Ambrosia psilos- 
tachya; bitterweed, Ambrosia trifidaintegrifolia; rough pigweed, Amaranthus retrojlexus. 




PRELIMINARY REPORT ON ALFALFA WEEVIL. 25 

MIGRATION AND DIFFUSION. 

There are two periods during which the adult insects migrate, more 
or less aided by the winds and perhaps to a less extent by other 
agencies. Such as have not hibernated directly in the alfalfa fields 
become active in early spring and fly about freely, seeking 
such fields in which to deposit their eggs. This spring migration 
covers a considerable period of time — about six weeks, as estimated 
by Mr. Titus. As the females are more or less heavily laden with 
eggs, however, the flight of the individual is perceptibly shorter than 
in the second, or summer, migration, the season for which begins 
early in June and continues for three or four weeks. Another reason 
for the shorter flight in spring is that the beetles are searching about, 
not for places of hibernation, but for breeding places. Having found 
these, they naturally would not go farther unless carried by the 
winds. In case of a summer flight, however, the conditions are 
altogether different. This is the season during which most nomadic 
insects become more widely diffused. At this time the beetles fly 
high in the air and apparently over long distances. They are also 
to be observed crawling about in almost every situation, as with the 
larger species, Hypera punctata, which may be observed wandering 
aimlessly over the pavements in the midst of large cities. Then, 
too, they appear to float about freely on the surface of water, and 
are doubtless carried long distances down stream by the current. 
We know this is true in the case of irrigating ditches and canals, and 
it is also true of the larger species just mentioned in case of streams 
in the East. This habit of the beetles in hiding themselves away in 
any crevice or aperture that will accommodate them doubtless has 
considerable to do with their diffusion. As a matter of fact, how- 
ever, it is absolutely impossible to lay down any law that appears 
to regulate the diffusion of the insect. There are instances where it 
would seem almost impossible to prevent the distribution of the pest, 
and yet most careful examination has failed to reveal anything of 
this sort. For a considerable time after the alfalfa weevil became 
abundant about Salt Lake and Murray hay was shipped from these 
points to Ely, Nev. This, too, in the midst of the season, when it 
would seem impossible to transport hay from these points to its 
destination without carrying greater or less numbers of the weevil. 
Notwithstanding this, years have gone by, and during the summer 
of 1911 two assistants examined the country about Ely most care- 
fully without finding a single alfalfa weevil or any indications that 
it had ever existed there. While it is possible to account for the 
spread of the insect theoretically, we can not as yet account for its 
diffusion to the northeast into adjacent sections of Wyoming and 
Idaho. It does not appear to have entered Idaho by way of the 
Cache Valley, although Mr. Titus found beetles on a coal car at 



26 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

Cache Junction in 1910. It does, however, occur in the Bear River 
Valley from Evanston, Almy, and Lyman, Wyo., northward into 
Bear Lake County in extreme southeastern Idaho. Previous obser- 
vations would indicate that by a natural diffusion the insect has 
spread a distance of about 30 miles each year. As a matter of fact, 
the beetles are continually being found where least expected, and 
they have not been found where, judging from their habits, we would 
feel most confident of their occurrence. 

The most rapid dispersion of the insect during the last two years 
has been toward the northeast from the original point of infestation 
in the Salt Lake Valley. Its injury is now noticeable wherever 
alfalfa is grown in the river valleys east of Ogden to the Wyoming 
State line and northward to the southern extremity of Bear Lake. 
It is known to occur, however, as previously stated, as far north as 
Cokeville, Wyo., and southward to Evanston and Lyman, where 
specimens were taken during the summer of 1911. This north- 
eastward trend of diffusion in the weevil must be considered in con- 
nection with prevailing southwest winds at the time when the beetles 
are flying, and, in fact, careful search over the newly infested territory 
seems to render it highly probable that to this cause is due this 
northeastward diffusion. The finding of individual larva 1 well 
scattered over W'yoming fields with little or no indications of intro- 
duction by human agencies, together with the finding of larvae in an 
irrigated valley isolated from other cultivated crops by 35 miles of 
dry desert country, are conditions hard to explain in any other way 
than that "the south winds of spring and summer have resulted in 
carrying flying beetles over low mountain ranges to fertile fields 
beyond. To just what extent the winds are able to carry the adults 
into new territory is not known, but at any rate migration in other 
directions has taken place much less rapidly. 

FIELD EXPERIMENTS IN DESTROYING THE ALFALFA WEEVIL. 

Several extended series of experiments in destroying the alfalfa 
weevil were carried out at various points in the infested territory 
in Utah, but only those that have shown the best results will here be 
mentioned. 

Quite naturally, a measure that will destroy a greater or less 
number of the insects and at the same time encourage the growth 
of the plant, and is of practical application, will not only be the most 
attractive one to the farmer but will result in a double benefit. For 
this reason disking was looked upon as probably offering the best 
results. It was thought that by disking and spraying a more rapid 
growth of the alfalfa plants would be secured, and by following this 
with the use of a brush drag a great many of the larva? would be 
crushed and destroyed. Mr. Ainslie's observations made in 1910 



Meld experiments in destroying weevil. 2*7 

indicate, however, that the brush drag does not destroy as many of 
the larvae as one would suppose, and for this reason some harsher 
measures have been put into application during the season of 1911. 

Street-Sweeper Experiments. 

The ordinary street sweeper, such as is used in our cities, appears 
to be a most thorough measure of destroying the pupae. This much 
was determined by the Utah Experiment Station. A street sweeper 
(PI. V, fig. 1) was used in a field on June 22, 1911. While examina- 
ation showed that the result of this treatment, at this time, was to 
kill most of the larvae and pupae, it did not kill a great percentage of 
the adult weevils, which had already developed in large numbers. 
It would have been much better had this work been carried out about 
two weeks earlier; not only the condition of this field but of others 
in the neighborhood treated between June 14 and July 1 indicated 
that considerable good had resulted from this treatment even at this 
late season. On another farm, owned by Mr. Breeze, southwest of 
Salt Lake City, a field was swept with the street sweeper about the 
14th of June with a view of interfering with the work of the weevil. 

By July 7 the alfalfa in the Breeze field was about 20 inches high 
with very few weevils present. (See PI. V, fig. 2.) Twenty days 
later the alfalfa was 30 inches high and in full bloom, being ready for 
the taking of a second crop. Just across the road from this farm 
was a field where no treatment whatever had been applied against the 
weevil. In this field the alfalfa plants were only about a foot in 
height and very much delayed (PI. V, fig. 3). This seems to indicate 
that as a protection for the second crop the measure has considerable 
value. The drawback here is in the expense of a street sweeper, 
although of course where the members of a community club together, 
or in case of very large alfalfa fields of several hundred acres, the 
first cost of this sweeping machine would not constitute such an 
important item. 

Wire-Brush Experiment. 

A 13-acre field of alfalfa 7 years old had been disked in the spring 
of 1910. The first crop of alfalfa was reported to have been reduced 
to one-half by attack of the weevil. A weevil-collecting machine 
had also been used on this first crop, but there were still enough of 
the weevils left in the field to greatly retard the second crop. It was 
disked and dragged again and a fairly good yield of the second crop 
was secured. This was also true of the third crop in this same field. 

On May 15, 1911, there was a good stand of alfalfa in this same 
field. One irrigation had at this date been applied. The plants 
were a little over a foot in height, and while at the time, May 15, they 
were in fairly good condition they were heavily infested with weevil 
larvae. The gathering machine was used twice between the 17th and 



28 PRELIMINARY REPORT ON ALPALEA WEEVIL. 

25th of May, and observations made at the time indicate that while 
many of the full-grown larvae were collected, most of the smaller 
ones were left among the buds. On May 29 the held received a 
second irrigation. The larvae at this time were very abundant; the 
gathering machine, too, had retarded the growth of the plants by 
breaking off the growing tips and some of the plants themselves had 
been broken down by the collecting machine. As a result the alfalfa 
had apparently made little or no growth since about the 22d, and its 
value as forage was at that time rapidly decreasing. 

A wire-brush machine (PI. VI, fig. 1) was constructed by Mr. L. 
Hemenway by bolting about, 30 pieces of No. 8 steel wire 7 inches 
long between iron clamps on each spring tooth of an old spring-tooth 
cultivator. The ground was gone over with one of these on June 1, 
as soon as the hay had been removed. The jumping action of the 
spring, together with the wire brushes, proved very effective in crush- 
ing larva? and pupa? among the stubble. The field was then gone 
over with a plank leveler, shown in Plate VIII, figure 2, with square 
iron edges bolted to a plank. June 7, the field received another 
brushing with the wire-brush machine, which crushed cocoons and 
larvae. By June 13 the second crop in this field had started nicely 
with very few weevils present. In another field near by no attempt 
had been made to treat it or to remove the weevil, and this field was 
taken as a check on the one under treatment. An examination at 
this time showed that when the former field was in good condition, 
with few larvae, the field that had received no treatment was bare 
and brown from their attack. 

On June 22 the second crop of alfalfa on the treated field was about 
8 inches high, while the unworked field was still bare and its condi- 
tion, on June 27, is shown in Plate VI, figure 3. By the 27th the 
alfalfa in the treated field was about 1 foot in height (see PL VI, 
fig. 2), the stand extra good, and the treatment had seemed to free 
the field from weeds and other foreign growth. By July 7 the plants 
were about 2 feet in height, while, of course, both the adults and 
larvae could be found to some extent in this field. July 27 the second 
crop harvested 2 tons per acre, selling at $9 per ton in the field. The 
field at time of harvest of second crop is illustrated in Plate VII, 
figure 1 . The unworked field, however, was making an inferior second 
crop, coming just a little in advance of the third crop in the treated 
field. 

From the treated field there was also a fourth crop of hay secured. 
The field was photographed on October 9, 1911, and the yield of hay 
is illustrated in Plate VII, figure 2. The condition of the check field 
a few days later, October 12, is shown in Plate VII, figure 3; here the 
second and third crops were both not only badly damaged, but so 
delayed in growth of alfalfa that, as shown by the illustration, no 
fourth crop was secured at all. 



Bui. 1 1 2, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate V. 




Fig. 1.— Street sweeper in operation on alfalfa field after first crop was removed. Larvae and pupae 
were crushed by the rotary brush. Photographed June 14, 1911. (Original.) 




Fig. 2. — Second crop ready to cut in the field on which street sweeper was used June 14, 1911. Good 
stand and good crop. Photographed July 27, 1911. (Original.) 




Fig. 3. — Second crop of alfalfa growing on field where no treatment was given. Crop short and about 
two weeks behind that of the field shown in figure 2. Photographed July 27, 1911. (Original.) 



Field Experiments Against the Alfalfa Weevil. 



Bui. 1 12, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VI. 




Fig. 1. — Wire-brush cultivator in operation on alfalfa field after first crop was removed. The brushes 
crush the larvae and pupae on the ground at this time. Photographed June 7, 1911. (Original.) 




Fig. 2. — Second crop of alfalfa growing nicely as a result of treatment given. (See fig. 1, above.) 
Larvae and pupae were killed, so that second crop suffered only slight injury. (Original.) 




Fig. 3. — Condition of untreated fields about June. Photographed June 27, 1911. (Original.) 
Field Experiments Against the Alfalfa Weevil. 



Bui. 112, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VII 




Fig. i. — Second crop of alfalfa, estimated at 2 tons per acre, secured from field treated with wire- 
brush cultivator. Photographed August 2, 1911. (Original.) 




Fig. 2. — Fourth crop of alfalfa secured from field where brush cultivator was used. Photographed 
October 9, 1911. (Original.) 




Fig. 3.— Condition of field used as check (PI. V, fig. 3). The second and third crops on this field 
made little growth and were much delayed, so what would correspond to the fourth crop was 
caught by frost. Photographed October' 12, 1911. (Original.) 



Field Experiments Against the Alfalfa Weevil. 



Bui. 112, Bureau of Entomology, U. S. Dept. of Agricultuie. 



Plate VIII. 









JMSfiLV .vw^ft^fc^xu* 


"-'Sl^tiLi 











Fig. 1. — Alfalfa field after first crop was removed, severely disked preparatory to application of 
"mudding" process against the alfalfa weevil. Photographed June 21, 1911. (Original.) 







Fig. 2. — Following the irrigation water with a drag, to "puddle" the weevils in the mud. 
Photographed June 22, 1911. 



Field Experiments Against the Alfalfa Weevil. 



Bui. 11 2, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate IX. 




Fig. 1. — Second crop of alfalfa in field treated by "mudding" process. Crop growing well and not 
seriously damaged by the alfalfa weevil. Photographed June 10, 1911. (Original.) 




Fig. 2. — Condition of untreated fields at time photograph shown in figure 1 was taken. The 
alfalfa weevils have prevented the second crop from starting. Photograph taken July 10, 
1911. (Original.) 




Fig. 3. — Patch of first crop left in field shown in figure 1, illustrating how the larvae weredissem- 
inated from the first crop into the field where the weevil had been killed by the " mudding " 
process. Photograph taken July 10, 1911. (Original.) 



Field Experiments Against the Alfalfa Weevil. 



field experiments in destroying weevil. 29 

Cultivation in Connection with Irrigation. 

For an experiment to determine the value of cultivation in connec- 
tion with irrigation in controlling the alfalfa weevil a field was selected 
on a farm belonging to Mr. Hansen, 1 mile southeast of Sandy, 
Utah, containing 16 acres. The soil was a light sandy loam. Some 
of the weevils had been noticed in this field in 1908 and also in 1909, 
while the first crop of 1910 was severely damaged and the second also 
suffered considerable loss. May 11, 1911, the field was irrigated, the 
infestation being considered heavy. The first crop was cut during 
the week ending June 10. The plants were about 9 or 10 inches high 
and the hay yielded less than 1 ton per acre of very poor quality. 
This field was again irrigated and the more elevated portion of it 
worked with a spring- tooth harrow while the surface was still soft 
from the irrigation. This treatment was repeated and when finished 
the field had very much the appearance of any cultivated field, 
little resembling a meadow. (See PL VIII, fig. 1.) 

On June 22, while the land was still soft and muddy, a light irriga- 
tion was given it, so that the water collecting in the lower portion of 
the field stood to a depth of 2 or 3 inches. Four horses were hitched 
to a plank leveler and dragged through this mud, as shown in Plate 

VIII, figure 2. This thoroughly "puddled" the weevil in all of its 
stages beneath the surface. 

By the 30th of June a second crop was starting very nicely while 
neighboring untreated fields were being retarded by the continued 
attacks of the weevil. Ten days later the plants were about 12 
inches high with very few of either larvae or beetles present. How- 
ever, a patch had been left uncut and unworked in one corner of this 
field and here the first crop of alfalfa was still standing. (See PI. 

IX, fig. 3, at the right.) 

There were a great many larvse and beetles on this patch, which 
disseminated themselves into the growing alfalfa where the mudding 
process had been practiced, destroying a strip about 1 rod in width, 
clearly shown in Plate IX, figure 3. The second crop in this field, 
July 10, 18 days after the mudding experiment was carried out, was 
about 14 inches high. (See PI. IX, fig. 1.) 

In a near-by untreated field at the same time, four weeks after the 
first cutting was made, the condition is shown in Plate IX, figure 2. 

Burning Machine. 

Several field experiments were carried out with a machine con- 
structed with the idea of burning over alfalfa fields after the removal 
of the first crop for the purpose of destroying the weevils in any stage 
of development remaining in the field. The machine, as shown in 
Plate X, figure 1, consisted of an iron frame 9 feet square, 12 inches 



30 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

high in front, and adjustable in the rear. The top was of light sheet 
iron bolted to the frame. 

Oil was pumped from a barrel in the conveyance to which this 
machine was attached and forced through a rubber hose into a supply 
pipe which fed the nozzles and burners underneath. The oil under 
pressure came forth from the burners as a mist of fire blowing into the 
stubble and against the ground. 

The sheet-iron cover served to hold the heat down while this oven 
passed slowly over the surface. In its unperfected state the machine 
did effective work and offered ideas of value, warranting the construc- 
tion of more efficient burners. 

In fields where there was a clean stand of alfalfa stubble this 
machine did very well in burning vegetation and destroying all insect 
life above the surface of the ground. Where many weeds, especially 
dandelions, were present, the insects found protection under the green 
leaves. Where parts of fields were burned over, the unburned area 
showed no growth for several weeks on account of the continued 
weevil attack. The burned area turned green within a very much 
shorter time. 

REDUCTION IN QUALITY OF HAY CAUSED BY THE ALFALFA 

WEEVIL. 

While studying the alfalfa weevil on various farms in the Salt Lake 
Valley during the month of April, 1911, it was found that many farm- 
ers, through a shortage of forage, were feeding the weevil-injured 
hay of the first crop to their horses. This hay contained so many 
old cocoons and was so dusty from larval excrement and dead bodies 
of weevil larvae as to render it unfit as feed for horses. On several 
occasions horses were observed coughing from the effect of this dust. 
In fact, many farmers consider the first crop from severely 'infested 
fields almost valueless as horse feed. 

On June 12, 1911, at Alpine, Utah, when the new hay from the first 
crop was fed to work horses these began coughing almost immediately 
after starting to feed upon this injured hay. The hay contained 
large numbers of dead weevil larvae, some still on the skeletonized 
leaves and some in the freshly spun cocoons. On September 13 hay 
from the first crop, in stack, was examined at Lay ton, Utah, and 
found to be very dusty, containing many dead weevil larvae and also 
pupae. 

NATURAL ENEMIES. 

The natural enemies of the alfalfa weevil consist of vertebrates and 
invertebrates. The former have been studied by assistants of the 
Bureau of Biological Survey, and a list of species observed to attack 
the weevil is given herewith. 



NATURAL ENEMIES. 



31 




a b 

Fig. 9.— Nine-spotted lady-beetle (Coccinella 9-notata): 
a, Adult; 6, l;rva. Much enlarged. (From Chit" 
tenden.) 



The invertebrate enemies are divided between native species and 
those imported from Italy, the native being largely predaceous and 
the foreign all parasitic. 

Besides these, there are two fungous enemies, both of which affect 
the insect to a greater or less degree. 

Invertebrates. 

When a foreign species, like the alfalfa weevil, is introduced into a 
new country, some time is required for the native insects to find out 
that it is suitable for food, pre- 
cisely as man himself would 
under the same circumstances 
have to learn what products 
of a new country were edible. 
Besides, he would most, likely 
cultivate a taste for some of 
these things which at first were 
distasteful to him. Thus it is 
that native insect foes of in- 
troduced species begin slowty 
at first to prey upon them. 

The following native pre- 
daceous insects have been found attacking and devouring the alfalfa 
weevil : 

PREDACEOUS ENEMIES. 

A species of tiger-beetles, Cicindela imperfecta Lee, was in one 
instance observed to feed upon an alfalfa weevil larva in the field. 

Several other indi- 
SSjli J viduals belonging 
* W/*^^/j to the same species 
when taken to the 
laboratory readily 
devoured larvae. 

Three species of 
lady-beetles, Coc- 
cinella 9-notata, 
Hbst. (fig. 9), llip- 
podamia spuria 
Lee, and II. con- 
vergens Guer. 
(fig. 10), in the larval stage attacked and devoured half-grown larvae 
of the alfalfa weevil in the fields. Larvae so taken were brought into 
the laboratory and adults reared, from which specific determina- 
tions were made. In case of II. spuria the adult was also observed 
devouring larvae in the field. 

The malachid beetle, Collops bipunctatus (fig. 11), was repeatedly 
observed feeding upon the weevil larvae in the fields. 




Fig. 10. 



a b w c 

-Convergent lady-beetle (Ilippodamia convergens): a, Adult; 6, 
pupa; c, larva. Enlarged. (From Chittenden.) 



32 



PRELIMINARY REPORT ON ALFALFA WEEVIL. 



The tenebrionid beetle, Eleodes svldpennis Mann., was accused by 
farmers of feeding upon the larvae of the weevil and when taken to 

the laboratory it readily 
did this in confinement. 
An allied species, E. 
suturalis Say, was ob- 
served by Mr. E. O. G. 
Kelly to devour chinch 
bugs in the neighborhood 
of Wellington, Kans. In 
the latter instance the 
beetles seemed to prefer 
the partially decaying 
leaves of corn under 
which the chinch bugs 
were hiding. It is prob- 
able that while these in- 
sects may devour a- few of 
fig. ii.— TbBtw<hspottedCoiiops(.couopabipunctatusy. Aduit, the weevil larvae theyprefer 

Enlarged. (Original.) Qther &nd vegetable f ood 

The predaceous mite, Pediculoides ventricosus Newp. (figs. 12, 13), 
was introduced from Indiana in March, 1911, but was afterwards 





Fig. 12. — Pediculoides ventricosus, 
a mite predatory on the alfalfa 
weevil: Adult female before the 
abdomen has become inflated 
with eggs and young. In this 
condition the mite is nomadic 
and predatory. Greatly en- 
larged. (Redrawn from 
Brucker.) 




Fig. 13.— Pediculoides ventricosus: Adult female after the 
abdomen has become inflated with eggs and young. 
Greatly enlarged. (Redrawn from Brucker.) 



found a sufficient distance away from the points of introduction to 
show plainly that it was already an inhabitant of Utah, The results 



Bui. 1 12, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate X. 







" =B,iP ^| 


2 • 




ifc/w 








^^* 





Fig. 1.— Burning Machine Experimented with as a method of Destroying 
the Alfalfa Weevil. (Original.) 




Fig. 2.— Boxes Containing Parasites of the Larv/e and Pup/e of the 
Alfalfa Weevil, Showing how this Material was Imported into the 
United States from Italy. Photograph taken June, 1 91 1. (Original.) 




Fig. 3.— Boxes of Parasite Material Imported from Italy which Contain 
Egg Parasites of the Alfalfa Weevil. Photograph taken May, 1911. 
(Original.) 



NATURAL ENEMIES. 



33 



of experiments with this mite, which is so effective in destroying the 
jointworm in the East, were unsuccessful, as it was found that the 
mites would not attack either the larvae or the pupae. They fed 
freely upon the eggs of the weevil, where these were easily accessible, 
but they seemed unable to gain access into many of the egg masses 
through the' ordinary egg punctures. A single egg did not furnish 
sufficient food to bring 
one mite to maturity, 
and it would therefore 
necessarily perish; but 
where there were clus- 
ters of eggs in contact 
with each other, the 
female mite was able to 
shift her body about 
sufficiently to devour 
more than one egg and 
was thus enabled to 
reproduce. In the field, 
when placed in cages 
with an abundance of 
eggs of the alfalfa wee- 
vil, the mites appeared 
to make considerable 
headway in overcoming 
the weevil, but in no case 
could the effects of their 
attack be traced farther 
than 2 feet from the cage 
where they had been 
confined in the fields. 

A little mite (Trombidium) was found attached to the adult weevil 
beneath the wing covers, and while it was observed quite commonly 
in late summer and fall, so far as observations indicated it did not 
appear able to kill the host insect. A predaceous mite, Erythrseus 
arvensis Banks (fig. 14), was found by Mr. Ainslie feeding on eggs of 
the weevil in the egg punctures. The economic value of this species 
is as yet very obscure. Spiders are occasionally found feeding upon 
the larvae in the fields. Lace-wing flies (Chrysopa) fed upon the 
larvae in confinement when forced to do so, but preferred aphides. 
They were not observed to attack the weevil in any form in the fields. 
26200°— Bull. 112—12 3 




Fig. H. 



A predaceous mite, Erythrxus arvensis: Adult. 
enlarged. (Original.) 



Greatly 



34 PRELIMINARY REPORT OX ALFALFA WEEVIL. 

A NATIVE TRUE PARASITE. 

Only one specimen of a single species of a true parasite of the alfalfa 
weevil has "so far been found in America. This was* described by 
Mr. Viereck as JEnoplegimorpha phytonomi. It was found August 30, 
1911, at Hoytsville, Utah, in the form of a cocooned pupa within the 
cocoon of the alfalfa weevil. The specimen was picked up from the 
surface of the ground in a badly infested alfalfa field and the adult 
parasite reared. The adult emerged September 3. 

INTRODUCED PARASITES. 

Several species of parasites were sent over from the vicinity of 
Portici, Italy, by Mr. W. F. Fiske during April, May, and June, 1911. 




Fig. 15. — Anaphes sp., a mymarid egg parasite of the alfalfa weevil: Adult male; female antenna above 
at right. Greatly enlarged. (Original.) 

The egg parasites were obtained by collecting stems of alfalfa con- 
taining eggs of the alfalfa weevil, placing these in boxes (PL X, fig. 3), 
and transporting them by cold storage on steamers bound for New 
York. On arrival from Europe they were promptly forwarded by 
refrigerator express to their destination. Salt Lake City, Utah, where 
they were at once taken either to the laboratory at Salt Lake City 
(PL XIII, fig. 1) or to the laboratory at Murray (PL XIII, fig. 2). 

Parasites that attack the weevil after it has hatched and before it 
has developed to the adult were handled in much the same manner. 
The boxes in which they were consigned are shown in Plate X, figure 
2. The time required to transport these boxes from Portici, Italy, 
to Salt Lake City, Utah, was from 16 to 21 days. 



NATURAL ENEMIES, 



Egg Parasites. 



35 



There were two egg parasites, one, a true egg parasite developing 
within the egg, and the second, a parasite the eggs of which are prob- 
ably deposited in the alfalfa stems among, but not in, the eggs. The 
larva of the latter is predaceous on the masses of weevil eggs as placed 
by the female weevil, and among them it develops to the adult. 



MY.MARII) EC<; PARASITE. 



A mymarid egg parasite, Anaplies sp. (fig. 15), was found in all 
of the seven shipments received from Italy. It was received in all 
stages of development, except perhaps the egg and adult, and was 
either left in the same boxes, these being perforated with holes and 




Fig. 16. — Imported pteromalid egg parasite of the alfalfa woovil: Adult. Greatly enlarged. (Original.) 

glass tubes inserted (PI. XI, fig. 2), or placed in specially prepared 
boxes (PI. XI, fig. 3) which were also perforated and had glass tubes 
inserted. The parasites were reared from this imported material, 
and from the parent stock two generations were reared on American 
egg masses of the alfalfa weevil. The third generation, together with 
others of the first and second generations and natives from later ship- 
ments, was placed in field reproduction cages (PI. XII, fig. 3) to 
the number of about 300. These cages were overstocked with eggs 
by confining numbers of weevils in them. After about 10 days the 
covers to these cages were removed, thus allowing the generation of 
parasites that developed within them to escape and scatter freely 
over the fields. 

PTEROMALID EGG PARASITE. 

A pteromalid egg parasite (fig. 16) was likewise found in all of the 
seven importations. The larva (fig. 17) feeds externally on the egg 
masses in the alfalfa stems, later transforming to the pupa (fig. 18). 



36 



PRELIMINARY REPORT ON ALFALFA WEEVIL. 




The disposal and management of this species did not differ from that 
followed with the preceding, except that some of them were received 
too late in the season to use in the low valleys because»the majority 
of the eggs of the weevil had already hatched. Owing to this the 
parasites were taken to places in higher elevations 
where eggs of Phytonomus were still abundant. 
Approximately 460 were placed in field cages like 
those previously mentioned and treated in the 
same way. 

Mr. Fiske found this species to lie very effective in 
controlling the alfalfa weevil in Italy. 

Parasites of Larvae and Pup.e. 

The parasites of the larvae and pupae of the alfalfa 
weevil, which were five in number, did not appear in 
the earlier consignments from Italy and were confined 
ptcromaiid egg to the last three received at Salt Lake City May 16 

aiflS* 6 w°e f e'vn e to June 3 - In these three shipments were metal 

Greatlyeniarged. boxes (PL X, fig. 2), which included only the cocoons 

of the alfalfa weevil. These boxes were especially 

devised to guard against the accidental escape of adult insects of 

any species en route. 

After being removed from the boxes in which the cocoons were 
received, they were placed in parasite boxes of the larger type 
(PI. XI, fig. 3), where the parasites emerged and were 
separated from the weevils that had developed en route. 
Both weevils and parasites on emerging from the cocoons 
in the box would seek the light and appear in the glass 
tubes shown in the illustration, where they were readily 
separated and the weevils killed. The parasites were 
then transferred to glass cages (PI. XI, figs. 1, 4) which 
had been previously well stocked with larvae and cocoons. 



Fig. 17.— Larva of 



PTEROMALID LARVAL PARASITE. 




A pteromalid parasite of alfalfa weevil larvae (fig. 19, 
female; fig. 20, male) was received in only the later 
consignments. Thus far it has not been possible to deter- 
mine the species. In the laboratory rearings, preparatory 
to placing the parasites in the field cages, and later, the 
species was carried through live generations. (Fig. 21, a 
shows the pupa of the alfalfa weevil, with the egg (fig. 21, &) 
as it is placed on the pupa; fig. 22 shows the larva, and fig. 
23 shows it destroying the pupa of the alfalfa weevil; fig. 24 shows the 
pupa of the parasite itself.) In order to accomplish this, however, it 
was necessary to secure weevil larvae., as hosts for them, from high 



Fig. 18.— Pupa 
of p t e r o- 
m a 1 i (1 egg 
parasite " I 
1 h c alfalfa 
weevil. 
Greatly en- 
1 a r g c '1 . 
(,< iriginal.) 



Bui. 1 12, Bureau of Entomology, U. S. Depx. of Agriculture. 



Plate XI. 





Figs. 1 and 4.— Types of cages in which larval and pupal parasites of the alfalfa weevil were 
reared in "the laboratory. Photograph taken during June, 1911. (Original.) 




Figs. 2 and 3.— Boxes sealed and fitted with glass tubes into which imported parasites emerged and 
were separated in the laboratory. Photograph taken during May and June, 1911. (Original.) 



Introduction of Parasites of the Alfalfa Weevil. 



1 1 2, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XII 





Figs. 1 and 2.— Field Cages Used in Hibernation Experiments on the Alfalfa 
Weevil. (Original.) 




Fig. 3.— Planting a Colony of Imported Parasites of the Alfalfa Weevil 
in Utah in an Alfalfa Field. Photograph Taken during June, 1911. 
(Original.) 



NATURAL ENEMIES. 



37 



elevations and bring; these into the laboratory, thus supplying them 
artificially. There were 230 individuals liberated in field cages, the 
coverings of which were later removed, and 49 liberated directly 




Fig. 19.— Pteromalid parasite of larva and pupa of the alfalfa weevil: Adult female. Greatly enlarged. 

(Original.) 




Fig. 20.— Pteromalid parasite of larva and pupa of the alfalfa weevil: Adult male. Greatly enlarged. 

(Original.) 

into the open field. Observations have since shown that this species 
has actually colonized itself in the field; whether temporarily or per- 
manently it remains to be seen. 



38 



PEELTMINARY REPORT ON- ALFALFA WEEVIL. 



OTHER PARASITES. 





Fig. 22. — Pteromalid parasite 
of larva and pupa of the 
alfalfa weevil: Larva. 
Greatly enlarged. (Orig- 
inal.) 



The following three parasites came mainly in the last two shipments 
from Italy. The adult of one. species (Canidiella curculionis Thorns.) 
(fig. 25) oviposits in the larvas of the alfalfa weevil in different stages 
of development, but the offspring therefrom 

emerge from the 

cocoon spun by the 

weevil, the cocoons 

of the parasite always 

showing through the 

meshes of the cocoon 

of the weevil (see fig. 

27). This species has 

two generations an- 
nually and hibernates 

as cocooned larvae. 

The alfalfa stems 

Fig. 21.— Pteromalid parasite of larva from which the three 
and pupa of the alfalfa weevil: a, „ 

Enlarged pupa of alfalfa weevil with Species 01 parasites 

eggs of parasite in place; 6, egg, f tllis gl'OUp Were 
greatly enlarged. (Original.) , , 

reared were also in- 
fested by Apion pisi Fab., and therefore some or all of the group may 
perhaps also parasitize this latter insect. Owing to its small size, 
however, as compared to the parasites, this seems rather unlikely- 
The two additional species reared with the preceding 
are not definitely determinable, but 
one is Phygadeuon sp., and the 
other ma} r prove to be Mesocliorus 
nigripes Ratz. Of this latter spe- 
cies Mr. T. W. Wassiljew, a Russian 
entomologist, under date of Febru- 
ary 6, 1911, wrote us: 

I wish to say that I am able to give you 
only one instance of a parasite having been 
found, and that was in the vicinity of Tasch- 
kent (Turkestan), where I noticed in the 
past year [1910] that over 20 per cent of the 
larvae of P. variabilis were attacked by an 
Ichneumon parasite. Unfortunately I do 
not know the name of this species of para- 
Bite at the present time, other than that it be- 
longs to the Ichneumonidse. Judging from 
the elliptical, thick-shelled cocoon it might 
possibly have been Mesochorus nigripes Ratz., which Mr. Ratzeburg (The Ichneu- 
monidse, III, p. L20) gives as a parasite of P. rumicus. 

All of these parasites resemble each other to a certain degree, and 
figure 25 will suffice to illustrate them, for the present at least. At 
the present stage of this experiment in introducing parasites of the 





Fig. 23.— Larva of ptero- 
malid parasite attack- 
ing pupa of alfalfa 
w i' c v i 1 . Enlarged. 
(Original.) 



Fig. 24.— Pupa of 

pteromalid para- 
site shown in fig- 
ures 22 and J:;. 
Greatly enlarged. 
(Original.) 



NATURAL ENEMIES. 



39 



alfalfa weevil the possibility of permanent establishment and future 
efficiency in the case of these species seems rather more encourag- 
ing than in case of the others. During June, 1911, 40 individuals 
reared from imported cocoons were placed in field cages artificially 
overstocked with weevil larvae, the cage covers being removed later. 
Besides this, there is at present on hand a considerable amount of 
hibernating material (PI. XII, figs. 1, 2) artificially reared in the 
Murray laboratory (PI. XIII, fig. 2), which will be allowed to escape, 
naturally, into the alfalfa fields. 




Fig. 25. 



-Canidiella curciiJionis, a parasite of the alfalfa weevil: Adult female; lateral view of abdomen 
of same below, at right. Enlarged. (Original.) 



The parasite Itopleciis masculator Fab. (fig. 26) differs from the 
preceding by reason of the fact that it pupates entirely within the 
pupa of its host. It is known to be a primary parasite, but the num- 
ber so far secured is too limited to warrant any discussion regarding 
it, or any predictions as to its future in America. 

Of the eighth and last of these parasites, Hemiteles sp., very little 
is known either in Europe or America, and with the obscurity surround- 
ing its habits it may prove to be either a primary or secondary 
parasite, a friend or an enemy of the others. It is therefore being 
handled with the utmost caution, none having been liberated either 
in the fields or in field cases. 



40 preliminary report on alfalfa weevil. 

Vertebrates. 

During the season of 1911 the Biological Survey, at the suggestion 
of the writer, kindly; detailed an assistant, Mr. E. R. Kalmbach, to 
study the bird and other vertebrate enemies of the alfalfa weevil, 
and the following is a list of vertebrates found to feed on the alfalfa 
weevil in Utah, as determined by Mr. Kalmbach, May 7, 1911, to 
July 25, 1911. 

Wilson's phalarope, Steganopus tricolor; killdeer, Oxyechus vociferus; valley quail, 
Lophortyx californica vallicola; mourning dove, Zenaidura macroura carolinensis; red- 
shafted flicker, Cola pics cafcr collaris; Arkansas kingbird, Tyrannus verticalis; Say's 




Fig. 26.—Itoplectis masculator, a parasite of the alfalfa weevil: Adult female; lateral view of first abdominal 
segment at right. Much enlarged. (Original.) 

phoebe, SSayorrtis sayus; Traill's flycatcher, Empidonax trailli; desert horned lark, 
Otocoris alpestris leucolsemu; magpie, Pica pica hudsonia; bobolink, Dolichonyx oryzi- 
rorus; eowbird, Molothrus ater; yellow-headed blackbird, Xanthocephalus xantho- 
cephalus; thick-billed red-winged blackbird, Agelaius phozniceusfortis; Western mead- 
owlark, Sturnella neglecta; Bullock's oriole, Icterus bullocki; Brewer's blackbird, 
Euphagus cyanocephalus; house finch, Carpodacus m ex icanus frontalis; English sparrow, 
Passer domestical: Western vesper sparrow, Pooecetes gramineus confirm; Western 
savannah sparrow, Passerculus savannarum alaudinus; Western lark sparrow, Chon- 
destes grammacus strigatus; white-throated sparrow, Zonotrichia albicollis; Brewer's 
sparrow, Spizella breweri; Western chipping sparrow, Spizella socialis arizonse; desert 
song sparrow, Melospiza melodia fallax; green-tailed towhee, Oreospiza chlorwa; black- 



Bui. 1 12, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XIII. 





Figs. 1 and 2.— Laboratories of the Bureau of Entomology, U. S. De- 
partment of Agriculture, at Salt Lake City and Murray, Utah. 

(Original.) 




NATURAL ENEMIES. 41 

headed grosbeak, Zamclodia melanocephala; rough-winged swallow, Stelgidopteryx 
serripennis; sage thrasher, Oreoscoptes montanus; Western robin, Planesticus migratorius 
propinquus; Rocky Mountain toad, Bufo lentiginosus ivoodhousi; leopard frog, Rana 
pipiens; salamander, Amblystoma sp. 

Fungous Enemies. 

Whenever the larger species Hypera punctata (fig. 2) becomes 
excessively abundant east of the Mississippi River, myriads of 
these larva? may be observed coiled about 
the uppermost tip of blades of grass or 
similar vegetation, where they soon die and 
become black. These are apparently de- 
stroyed by a fungus, Empusa sphserosperma. 
When investigations of the alfalfa weevil 
were first undertaken there were great 
numbers of these dead and dying larvae to 
be found in Washington, D. C, in Potomac FlG . 2 7.-coc7on ofTt'v alfalfa weevil 
Park. Thev were gathered up and sent showing cocoon of the parasite 

~ ,. T , r*.. i •■ i • ,, Canidiella cureulionis within. Much 

out to Salt Lake City and placed m the enlarged. (Original.) 
hands of Mr. Ainslie with the hope of in- 
troducing this fungus among the larvae of the alfalfa weevil. The 
experiment appeared to have been a failure, and it was thought 
that the climate of Utah was too dry to enable this fungus to 
exist there. Later this larger species was found in Utah, as has 
already been stated, and during the spring of 1911 the fungus 
was found in the vicinity of Salt Lake City. Apparently, how- 
ever, the fungus does not affect the larvae to the same extent 
that it does here in the East, except after these have reached 
their full size and constructed their cocoons. Larvae of the alfalfa 
weevil (fig. 5) and pupae (fig. 7) soon began to be observed in the 
cocoon (fig. 6) dead and thoroughly permeated with this fungus. 
No individuals in any case were found dead excepting within their 
cocoons. On June 13 in the vicinity of Salt Lake City it was 
estimated that one-fifth of the cocoons contained dead larvae or 
pupae. ' In the Weber Valley, about Hoytsville, Utah, on the last 
of August, it was found that of 580 cocoons examined 258, or 44.5 
per cent, were dead, partly at least because of infestation by this 
fungus. Examination at another point showed that 38 percent had 
apparently died from the same cause. To all appearances, then, tins 
was more effective in killing the alfalfa weevil than all other natural 
enemies combined. « 



INDEX. 

Page. 

/Enoplegimorpha phytonomi, parasit e of al Ealfa weevil 34 

Agelaius pJiceniceusforti3, enemy of alfalfa weevil 40 

Alfalfa, (see also Medicago saliva). 

duration of growing which should be allowed in weevil-infested districts . 1 2 

food plant of alfalfa weevil 1-41 

clover-leaf weevil (Ilypera punctata 1 15 

hay, reduction in quality caused by alfalfa weevil 30 

varieties experimented with in relation to alfalfa weevil 14 

weevil, adult, description and habits 11-12. 15-17 

allied species introduced from Europe 9 

appearance of second species in Utah 15 

cocoon, description 12 

cocooning and pupating 23-24 

cooperation of Bureau of Entomology and Utah Experiment 

Station 12-14 

with other bureaus of U. S. Department of Agricul- 
ture 14-15 

description and seasonal history 15-24 

diffusion 25-26 

distribution in the old world 9 

egg 12. 17-19 

laying period ] 9-20 

evidence of partial second generation 20-21 

field experiments in destruction 26-30 

first appearance in United States 9-10 

food plants 24 

generally known in old world as Phytonom us variabilis 15 

held in check in old world by natural enemies 15 

hibernation 12 

incorrectly called Phytonomus marinas 15 

in Utah 1-41 

investigations by Utah Experiment Station 11-12 

of vertebrate enemies 15 

larva 12. 21-22 

larval peri< id 22-23 

less destructive in old world than in United States 15 

means of dissemination (see also Alfalfa weevil, diffusion) 12 

migration 25-26 

natural enemies 30-4 1 

oviposition 17 

possible confusion with clover-leaf weevil (Ilypera punctata) ... 15 

pupating and cocooning 23-24 

reduction in quality of alfalfa hay due to work 30 

remedies, burning machine 29-30 

cultivation in connection with irrigation 29 

43 



44 PRELIMINARY REPORT OX ALFALFA WEEVIL; 

Page. 

Alfalfa, weevil) remedies, recommended by Utali Experiment Station 12 

street-sweeper experiments * 27 

wire-brush experiment 27—28 

seasonal history and description ] 5-24 

spread in Utah and West 10 

Amaranthus retroflexus refused as food by alfalfa weevil 24 

Amblystoma sp., enemy of alfalfa weevil 40 

A mbrosia psilostachya refused as food 1 >y alfalfa weevil 24 

trifida iritegrifolia refused as fi iod by alfalfa weevil 24 

Anaphes sp., parasite of alfalfa weevil 35 

Astragalus arietinus oviposited in by alfalfa weevil 17 

utahensis, food plant of alfalfa weevil 17, 24 

on ophilus eaten by alfalfa weevil 24 

Bean, string. (See Phaseolus vulgaris.) 

Birds, enemies of alfalfa weevil 15, 30-31, 40 

Bitterweed. . (See Ambrosia psilostachya and A. trifida integrifolia • 
Blackbird, Brewer's. (See Euphagus cyanocephalus. i 

thick-billed red-winged. (See Agelaius phozniceus fortis.) 
yellow-headed. (See Xanthocephalus xanthocephalus. ) 
Bobolink. (See Dolichonyx oryzivorus.) 

Brush drag against alfalfa weevil 12 

Bufo lentiginosus woodhousei, enemy of alfalfa weevil 40 

Burning machine against alfalfa weevil 29-30 

Canidiella curculionis, parasite of alfalfa weevil 38 

Carpodacus meximn us frontalis, enemy of alfalfa weevil 40 

( % nopodium album refused as food by alfalfa weevil 24 

Chick pea. (See Pea, chick.) 

Chinch bug (Blissus leucoptcrus), prey of Eleodcs suturalis 32 

< 'hondestes grammacus strigatus, enemy of alfalfa weevil 40 

Chrysopa. (See Lace-wing flies.) 

dcvndela imperfecta, enemy of alfalfa weevil 31 

Clean culture to prevent alfalfa weevils from hibernating 12 

( 7, ome serrulata eaten by alfalfa weevil : 24 

Clover, alsike. (See Trifolium hybridum .) 

food plant of clover-leaf weevil (Hypera punctata) 15 

leaf weevil (Hypera punctata) (see also Phytonomus punctatus). 

damage to clover 15 

first appearance in Idaho and Utah 15 

red. (See Trifolium pratense.) 
white. (See Trifolium repens.) 

sweet. (See Melilotus alba.) 
yellow sweet. (See Melilotus indica.) 

Coccinclla 9-notata, enemy of alfalfa weevil 31 

( 'olaptcs cafer rollaris, enemy of alfalfa weevil 40 

( 'ollops biputicla/us, enemy of alfalfa weevil 31 

Cowbird. (See Molothrus ater.) 

Cultivation against alfalfa weevil 29 

. in connection with irrigation against alfalfa weevil 29 

Discing against alfalfa weevil 12 

Dolichonyx oryzivorus, enemy of alfalfa weevil 40 

Dove, mourning. (See Zenaidura macroura.) 
Drag. (See Brush drag.) 

Eleodea mlcipennis, enemy of alfalfa weevil : 32 

suturalis, enemy of chinch bug (Blissus leucopterus) 32 



INDEX. 45 

Page. 

Empidonax trailH, enemy of alfalfa weevil 40 

Empusa sphgerosperma, fungous enemy of alfalfa weevil 40-41 

Hypera punctata ...-. 40-4 1 

Erythrseus arvensis, enemy of alfalfa weevil 33 

F.u jihagus cyanocephalus, enemy of alfalfa weevil ' 40 

Fenugreek. (See Trigonella fcen umgrsecum.) 
Finch, house. (See Carpodacus mexicanus frontalis.) 
Flicker, red-shafted. (See Colaplrs cqfer eoUaris.) 
Flycatcher, Traill's. (See Empidonax trailli.) 
Frog, leopard. (See Rana'pipiens.) 

Fungous enemies infecting alfalfa weevil 40-41 

Grass, birds-knot. (See Polygonum aviculare.) 

stem oviposited in by alfalfa weevil 17 

Grosbeak, black-headed. (See Zamelodia melanocephala.) 
Ground cherry. (See Physalis longifolia(?)) . 
plum. (See Astragalus arietinus.) 

Hedysarum mackenzii eaten by alfalfa weevil 24 

Hemiteles sp., parasite of alfalfa weevil 39 

Hippodamia convergens, enemy of alfalfa weevil 31 

spuria, enemy of alfalfa weevil 31 

Hypera punctata, accidental transportation from New York to Michigan 9 

attacked by fungus 40 

first appearance in Idaho and Utah 15 

Icterus bullocH, enemy of alfalfa weevil 40 

Itoplectis masculator, parasite of alfalfa weevil 39 

Killdeer. (See Oxyechus rod ferns.) 

Kingbird, Arkansas. (See Tyrannus verticalis.) 

Lace-wing flies, enemies of alfalfa weevil 33 

Lactuca scariola refused as food by alfalfa weevil 24 

Lamb's-quarters. (See Chenopodium album.) 

Lark, desert horned. (See Otocoris alpestris hucohrma.) 

Lathyrus Idtifolius refused as food by alfalfa weevil. 24 

odoratus, food plant of alfalfa weevil 24 

sativus eaten by alfalfa, weevil 24 

Leaves, eggs of alfalfa weevil deposited thereon 17 

Lettuce, prickly. (See Lactuca scariola.) 
Locust, black. (See Robinia pseudacada.) 

Lophortyx californica vallicola, enemy of alfalfa weevil ■ 40 

Lupinus sp. eaten by alfalfa weevil 24 

Magpie. (See Pica pica hudsonia. ! 

Mallow, round-leaved. (See Malva rotundifolia.) 

Malva rotundifolia refused as food by alfalfa weevil 24 

Meadowlark, western. (See Sturnella neglecta.) 

Mi dicago ciKaris, experiment against alfalfa weevil 14 

i ch in us, experiment against alfalfa weevil 14 

food plant of alfalfa weevil 24 

falcata, experiment against alfalfa weevil 14 

hispida confinis, experiment against alfalfa weevil 14 

food plant of alfalfa weevil 24 

n igra, experiment against alfalfa weevil 14 

food plant of alfalfa weevil 24 

terebellum, experiment against alfalfa weevil 14 

food plant of alfalfa weevil 24 



46 PRELIMINARY REPORT ON ALFALFA WEEVIL. 

Page. 

Medicrgo lupulina, experiment against alfalfa weevil 14 

food plant of alfalfa weevil 24 

in uricata, experiment against alfalfa weevil m 14 

f ( m id plant of alfalfa weevil 24 

orbicularis, experiment against alfalfa weevil 14 

food plant of alfalfa weevil 24 

ruthenica, experiment against alfalfa weevil 14 

sativa (see also Alfalfa). 

experiment against alfalfa weevil 14 

scutellata, experiment against alfalfa weevil 14 

food plant of alfalfa weevil ". 24 

Melilotus alba, food plant of alfalfa weevil 24 

imlica, food plant of alfalfa weevil 24 

Melospiza melodia fallax, enemy of alfalfa weevil 40 

Mcsochorus nigripes, parasite of alfalfa weevil 38 

Phytonomus rurnicis 38 

Molothrus ater, enemy of alfalfa weevil 40 

(Jreoscoptes montanus, enemy of alfalfa weevil 40 

Oreospiza chlorura, enemy of alfalfa weevil 40 

Oriole, Bullock's. (See Icterus bullocki.) 

Otocoris alpestris leucolsema, enemy of alfalfa weevil 40 

Oxyech as roci/erus, enemy of alfalfa weevil 40 

Passerculus savannarum alaudinus, enemy of alfalfa weevil 40 

Passer domesticus, enemy of alfalfa weevil 40 

Pea, chick, eaten by alfalfa weevil 24 

everlasting. (See Lathyrus latifolius.) 
garden. (See Pisum sativum.) 
sweet. (See Lathyrus odoratus.) 

Pediculoides ventricosus , enemy of alfalfa weevil 32-33 

Phaseolus vulgaris, food plant of alfalfa weevil 24 

Phoebe, Say's. (See Sayonvis sayus.) 

Phygadeuon sp., parasite of alfalfa weevil : 38 

Physalis longifolia refused as food by alfalfa weevil 24 

Phytonomus murinus, name incorrectly applied to alfalfa weevil 15 

nigrirostris, introduction into United States 9 

posticus. (See Alfalfa weevil.) 
punctatus (see also Hypera punctata). 

jninclalus= Ilyperu punctata 9 

introduction into United States 9 

rum ids, host of Mcsochorus n igripes 38 

variabilis, name given alfalfa weevil in old world 15 

Pica pirn hudsonia, enemy of alfalfa weevil 40 

Pigweed, rough. (See Amaranthus retroflexus.) 

Pisum sativum refused as food by alfalfa weevil 24 

Planesticus migratorius propinquus, enemy of alfalfa weevil 40 

Polygonum aviculare refused as food by alfalfa weevil 21 

Poceci tes gramineus confinis, enemy of alfalfa weevil 40 

Portulacq oleracea refused as food plant by alfalfa weevil 24 

Pteromalid egg parasite of alfalfa weevil 35-36 

larval parasite of alfalfa weevil 36-37 

Purslane. (See Portulaca oleracea.) 

Quail, valley. (See Lophortyx calif arnica vallicola.) 

Rami jiipit us, enemy of alfalfa weevil 40 



INDEX. 47 

Page. 

Robinia pseudacacia, food plant of alfalfa weevil 24 

Robin, western. (See Planestieus migratorius propinquus.) 
Salamander. (See Amblystoma sp. ) 

Sayornis sayus, enemy of alfalfa weevil 40 

Sheep, pasturing as remedy against alfalfa weevil 12 

Sparrow, Brewer's. (See Spizella breweri.) 

desert song. (See Melospiza melodia fallax.) 

English. (See Passer domesticus.) 

western chipping. (See Spizella socialis arizonae.) 

lark. (See Chondestes grammacus strigatus.) 
savannah. (See Passerculus savannarum alaudinus.) 
vesper. (See Pocecetes gramineus confinis.) 
white-throated. (See Zonotriehia albieollis.) 
Spider plant. (See Cleome serrulata.) 

Spiders, enemies of alfalfa weevil 33 

Spizella breiveri, enemy of alfalfa weevil 40 

socialis arizonae, enemy of alfalfa weevil 40 

Steganopus tricolor, enemy of alfalfa weevil 1 40 

Stelgidopteryx sempennis, enemy of alfalfa weevil 40 

Sturnella neglecta, enemy of alfalfa weevil 40 

Swallow, rough-winged. (See Stelgidopteryx serripennis.) 

Sweeper, street, against alfalfa weevil 27-28 

Sweet pea. (See Lathyrus odoratus.) 

Thrasher, sage. (See Oreoscoptes montanus.) 

Toad, Rocky Mountain. (See Bufo Untiginosus v oodhousei.) 

Towhee, green-tailed. (See Oreospiza chlorura.) 

Trifolium hybridum, food plant of alfalfa weevil 24 

pratense, food plant of alfalfa weevil 24 

repens, food plant of alfalfa weevil 24 

Trigonella fcenumgrsecum, food plant of alfalfa weevil 24 

Tyrannus verticalis, enemy of alfalfa weevil 40 

Vetch, hairy or winter. (See Vicia rillosa.) 
narrow-leaved. (See Vicia sp.) 
obtuse-leaved. (See Vicia sp.) 
spring. (See Vicia sativa alba.) 
Utah milk. (See Astragalus utahensis.) 

Vicia atropurpurea eaten by alfalfa weevil 24 

dispema eaten by alfalfa weevil 24 

sativa alba eaten by alfalfa weevil 24 

sp., food plant of alfalfa weevil 24 

villosa eaten by alfalfa weevil 24 

Weevil, alfalfa. (See Alfalfa weevil.) 
Wilson's phalarope. (See Steganopus tricolor.) 

Wire brush against alfalfa weevil 27-28 

Xanthocephalus xanthocephalus, enemy of alfalfa weevil 40 

Zamelodia melanocephala, enemy of alfalfa weevil : 40 

Zenaidura macroura carolinensis, enemy of alfalfa weevil 40 

Zonotriehia albieollis, enemy of alfalfa weevil 40 

o 



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